In 2014, Keller got drafted by the Pirates (see Transactions below).  

In 2015, Baseball America rated Keller as the 9th-best prospect in the Pirates organization. He dropped to #18 in the spring of 2016. He was at #2 before 2017 spring training, behind only OF Austin Meadows.

In the spring of 2018, Keller was ranked the #1 prospect in the Pirates' organization, ahead of Meadows this time. And he stayed at #1 in both the spring of 2019 and again in 2020, too.

Mitch is very coachable, anxious to learn and quick to implement.

To pitch or putt? That was the question Mitch Keller weighed when he was a high school sophomore. Keller was a dominant high school pitcher, but he also possessed talent on the golf course. He once shot a 2-under-par round in the Iowa high school state postseason tournaments. But Keller didn’t follow the path of Zach Johnson, a fellow Iowan with two major titles, including a Masters championship. Instead, Keller chose baseball.

"I kind of knew in the back of my head what I wanted to do. I kind of figured that if I was going to play college golf, I probably wouldn’t. It’s really hard to be a pro golfer. And I had already been told I could be a professional baseball player." (jdill@bradenton.com - April 2017)

2017-2018: Mitch was invited to play in the AFL Fall Stars Game.  Keller showed his stuff in a perfect opening frame.

Keller's 2019 Season: 

What went right? If you’re a fan of fielding-independent pitching numbers, you’re likely a believer in Keller. He posted a 3.19 FIP and 3.47 xFIP, both the best marks among active Pirates pitchers at the end of the season. Statcast predicts better days ahead, too, as Keller’s .256 expected average and .389 expected slugging percentage were well below the actual .348 average and .546 slugging percentage he allowed.

Those encouraging numbers were a product of Keller striking out 65 batters, walking 16 and allowing six homers in his 48 innings on the mound. If he maintains those rates while experiencing a dip in his absurdly high .478 batting average on balls in play (league average is around .300), he’ll be well on his way to fulfilling his potential.

It’s easy to like Keller’s easy, mid-90s fastball. His curveball is a weapon when he can convince opponents that he’s able to throw it for a strike as well as a swing-and-miss pitch. The slider he added earlier this year has diversified his arsenal. He threw 151.2 innings between Triple-A Indianapolis and Pittsburgh, setting him up for a full season’s worth of work next year. And there’s no doubt he learned a lot about how his stuff plays in the Majors by making 11 starts this season.

“Just a huge, huge, huge learning experience,” Keller said. “Everything about it was a learning experience, from the good outings to the bad ones to being sent down to being brought back up and everything in between. Just a huge learning experience.”

Best moment:  He went into the offseason on a high note, holding the Cubs to one run while striking out seven over five innings in his last start of the season. But his best outing overall was Aug. 23 against the Reds, the same team that welcomed him to the Majors on May 27 with a six-run first inning. Nearly three months after his big league debut, Keller permitted only one run on six hits and a walk while striking out nine at PNC Park. He established his 95 mph fastball in the strike zone, throwing 20 of 24 first-pitch strikes on the night, while mixing in legitimate swing-and-miss curveballs and sliders. Keller also set a season-high with 20 swinging strikes; only Jordan Lyles recorded more in one game for the Pirates this year.   (Adam Berry - MLB.com - Oct. 18, 2019)

Heading into 2020 Spring Training:  Keller is the latest pitching prospect to top the Pirates’ system, joining the likes of Gerrit Cole, Jameson Taillon and Tyler Glasnow in the last decade. Keller has flashed the pure stuff to be a top-of-the-rotation starter, though the Pirates haven’t gotten those results consistently from the previous group. Keller’s chances might be better. He will work with a new big league pitching coach, following the firing of Ray Searage, and likely a more updated organizational pitching philosophy, which has held Pirates pitching prospects back in recent years. (Tim Williams - BA Prospect Handbook - Spring 2020)

TRANSACTIONS

Keller worked on making his delivery before 2022 spring training and is hitting 100 mph with his FASTBALL.

In 2010, Mike Trout was an 18-year-old prospect tearing up the Midwest League with the Angels’ Class A affiliate in Cedar Rapids, Iowa. The way he played then stood out to a 14-year-old Cedar Rapids native by the name of Mitch Keller, who said he grew up watching Trout. Now he will get to face the best baseball player on the planet for the first time as Keller returns to the Majors at Angel Stadium.

Keller often went to the ballpark to watch the Cedar Rapids Kernels when Trout was on their roster. One home run Trout crushed over the batter’s eye, Keller said, was the “craziest thing I’ve ever seen.” So Keller’s excited to face Trout as well as Albert Pujols, but he’s not going to be too star-struck.

“If you start looking at them like that, then you’re already a step behind. I feel like I can go up against anybody with the stuff that I have, so I don’t really think about that,” Keller said before the Pirates’ 11-9 loss to the Cardinals. “It’ll be kind of cool to face Trout, though.”

“Obviously, getting back up to where you want to be is a good thing,” Keller said. “It feels really good to come back and get another opportunity.”

The Pirates sent Keller to Triple-A Indianapolis with a to-do list focused mostly on his pitch sequencing. Keller threw his fastball about 65 percent of the time in his first three starts, and he only used his curveball 9.1 percent of the time. Keller’s experience with the Pirates reinforced the importance of throwing his breaking balls for strikes, which he said he did more consistently after returning to Triple-A.

In eight Triple-A starts between his big league stints, Keller posted a 4.14 ERA while striking out 49 and walking 10 in 45.2 innings.

“I think it went really well. Just going over pitch sequencing and the splits of pitches, maybe a little bit less fastball and more off-speed,” Keller said. “Really working on throwing off-speed for strikes in any count.

“It kept hitters off-balance and just made my fastball play up a little bit more than it already did, just because they didn’t know it was coming. If I don’t do that, I’m going to get into a bad hitter’s count or I could walk them. My mentality was that I had to throw it for a strike.”

Following the 2015 season, Mitch spent time working on his mechanics in instructional league. “I really cleaned up my delivery, and I can get the ball where I want it now and consistently throws strikes,” Keller said. “I also have more power behind my pitches now. I feel stronger from the start and stay that way into the late innings.”

2016 Improvements: Keller began the season No. 14 on the Pirates' Top 30. He moved up to No. 5 on that list and firmly on the Top 100 at No. 76, as of October 2016. There's a chance that Keller is still under-ranked.

Making his full-season debut, the 20-year-old led the organization in WHIP, finished second in strikeouts and batting-average-against and third in ERA. A late promotion up to Bradenton resulted in a strong regular-season start and two postseason wins, the second of which came from tossing eight shutout innings. Keller could top the next wave of young Pirates pitching prospects making their way to Pittsburgh.

In 2016, Keller made a mechanical change to his delivery. Keller held his glove firmly above his belt, which enabled him to better locate his fastball to both sides of the plate. Mitch is learning to effectively mix his curveball and changeup into the mix to complement his fastball, which consistently sits at 94-96 mph and tops out at 98.

“The hitters aren’t sitting on my fastball anymore,” Keller said. “They have doubt in their mind. They don’t know what’s coming. That gears up the fastball, and when I throw the off-speed stuff, they end up chasing a lot.”

Mitch comes at hitters from a nice downhill plane from a high three-quarters arm slot. It is an easy delivery that gives him at least average control (a 60 grade). His arm circle has some length, with a wrist wrap in the back, but consistently throws strikes.

He could stand to tighten his delivery in order to improve his control.

"The key has been being able to command my fastball and throw changeups in different counts," Keller said. "That's been the main focus for me, to throw the changeup. I didn't throw a changeup at all in high school. It's made a huge difference for me."

A native of Cedar Rapids, Iowa, Keller grew up playing the game while admiring his brother Jon, who is three years and seven months older than Mitch. Jon pitched two years at the University of Nebraska before transferring to the University of Tampa. He wound up signing as Baltimore's 22nd-round pick in 2013.

"I watched my brother play in high school and then go on to play in college," Keller said. "I always wanted to do that, and then he got drafted. I guess I've always followed him in his footsteps and now we're both playing Minor League Baseball. We talk just about every day, about anything and everything. In the offseason we work out together and throw together. It's helped us both a lot. We push and encourage one another. It's a great situation for both of us." (Bill Ballew - 6/30/2016)

Part of Keller’s struggles in 2018 came because of mechanical problems on the backside of his delivery that led to his pitches coming out of his hand flat. He focused on eliminating those problems late in the season but still had the worst season of his career in terms of command. He was missing too much in the middle of the plate. (Spring, 2019)

Mitch's Scouting Grades: He has a 65 fastball, a 60 curveball, and a 50 changeup. He also rates a 60 for his above-average control. (Spring, 2018)

He generates a lot of groundballs because his heater generates good sink.

Keller should develop into a #2, or at least a #3, big league starter.

But after those starts, the 6-foot-3, 195-pound Keller showed the ability to make adjustments, down to the basics of his mechanics. A lights-out June led the Pirates to promote the 22-year-old to Triple-A Indianapolis on June 28. He finished his time at Altoona with a 2.72 ERA with 76 strikeouts in 86 innings.

“I think it was important for him to have a couple of starts that weren’t great and understand what adjustments he needed to make,” farm director Larry Broadway said. “I think he got off his back side a little bit, and when he does that, the ball gets a little flatter. It gets up and elevated.

Now, Keller is better able to self-correct delivery flaws. He also picked up a two-seam changeup grip to give him a pitch to complement his mid-90s fastball and plus 11-to-5 curveball. (Dustin Dopirak - Baseball America - 8/24/2018)

October 2018: Keller was named the MLB Pipeline Pitcher of the Year for the Pirates.

Anticipating his first start in the Major Leagues, Mitch has the following going for him in 2019.

Fastball: During Keller’s struggles in 2018, he saw his velocity dip, but it’s come back since. Outside of that one stretch he’s consistently been able to touch 97-98 mph with his fastball and sit 93-96 with good sink. If you saw the Futures Game, you saw the velocity, as he hit 99 in his one inning of work. He misses bats and gets weak contact on the ground as well with the pitch.

Curveball: An excellent 11-to-5 breaker, this is Keller’s other strikeout pitch. It’s a true downer breaking ball with a lot of bite. Look for him to lean on this pitch, which flashes plus often, to attack big league hitters.

Slider: This is a new pitch for Keller that he’s added to his repertoire this year. It’s a cutter-like pitch and it’s been an effective weapon for him, giving advanced hitters a different look. It might be a Major League average offering at this point.

Changeup: He’s worked on his changeup quite a bit over the years to get it up to Major League average. It does have some fade and sink to it, eliciting some ground-ball outs, but it might be his fourth pitch at this point.

Control: This was a plus part of his game until recently. His walk rate jumped in 2018 up to 3.5 BB/9 and he’s walked 3.8 per nine so far this year. Still, his career mark is 2.9, and he’s looked more like his old self in his four May starts, walking just 2.45 per nine during that stretch. When he repeats his delivery well, he is a strike-thrower, one who eventually could have above-average overall command.  (Mayo - mlb.com - 5/26/19)

MLB debut (May 27, 2019): The Pirates had essentially knocked themselves out of the game by the end of the first inning in Game 2 of their doubleheader with the Reds, but there were still positives to draw from their 8-1 loss. The main takeaway? Rookie Mitch Keller, making his Major League debut as a spot starter in this twin bill at Great American Ball Park, pitched well after a mostly disastrous opening inning.

“The entire volume of work, I saw improvement,” manager Clint Hurdle said. “He got punched hard early. And the hole was awful deep that was dug. From that point on, everything got better. The fastball was up, the breaking ball was up, the changeup was up. They hit it hard. After that, he responded well.”

The Pirates placed no inflated expectations on their prized pitcher, the club’s No. 1 prospect, according to MLB Pipeline, when they announced he would start Game 2. In fact, they made it clear ahead of time this was probably too early in Keller’s development for a promotion, and this was happening only out of necessity—their rotation and bullpen have been severely affected by injury and inconsistency, and they needed to dip into their system for a starter to help out during what was surely going to be a very long day at the ballpark.

And at first, it looked as if Keller may not make it out of that opening frame, which could have spelled disaster for the Pirates. They used four relievers in their Game 1 win, and even with the extra arm in the 'pen due to the 26th man rule, absorbing seven or eight innings would have been a struggle for any team, doubleheader or not.

But Keller settled in well, retiring eight batters in a row and allowing just one hit over his final three frames.

“I think just the first inning, I was a little amped up,” Keller said. “My off-speed pitches weren't as crisp as the second, third and fourth innings. I think that was the main thing. My fastball the first inning was pretty much the way it was the whole game.”

Keller, pitching in front of nearly 40 friends and family who made the trek from Iowa to watch his debut, faced 11 batters in the first inning. He issued walks to two of the first three, before logging his first Major League out—a strikeout of cleanup hitter Derek Dietrich. The dagger arrived two batters later, when Jose Iglesias launched a grand slam, putting the Reds ahead, 5-0.

“Changeup,” Keller said of the pitch to Iglesias. “Just a bad changeup.”

But Keller needed just 12 pitches to retire the side in the second, and he ended his 85-pitch outing with seven strikeouts.

The performance impressed at least one of the hitters he faced.

“He’s good. He’s got good stuff,” Dietrich said. “There’s no doubt about it. You saw some flashes. I didn’t see him the first at-bat very well. The second at-bat, I was like ‘one, two, three [snaps his fingers]’ and he just dotted three different pitches.

“He showed flashes like he’s got the stuff. Once he settles in and finds the routine and everything falls into place, he’ll probably be a top-of-the-line starter for them. Tough first go for him, of course. At least he got me with his first K, which sucks for me but for him, it’s all good.”

Keller threw north of 40 pitches in that opening frame, and had he not struck out Jesse Winker to end the rally, he probably would not have been given the chance to go out for the second.

Instead, Keller stayed in, which shaved several innings off the bullpen’s workload.

“The man's got an arm that you’ve got to take care of,” Hurdle said. “Winker’s his last hitter. If he doesn't get that guy out, he's out of the game, and we have to make up seven innings. We've got to find a way to patch that together, which we would have done. He got the man out and moved on. There was resilience, there was fight back.”

The No. 18 overall prospect in baseball, according to MLB Pipeline, Keller finished with 13 strikeouts over five innings. The 23-year-old yielded one hit and walked three, lowering his season ERA to 3.10 over 11 starts.

Aug 12, 2019: In the first start of his second Major League stint, Keller allowed two runs (one earned) over five innings and was backed by four home runs in a 10-2, skid-ending victory. Pittsburgh’s top prospect gave up five hits, two walks and hit a batter while striking out four.

“It’s incredible,” said Keller. “Growing up, I would never picture being here, where I’m at right now. It feels good to get the first [win] out of the way. Hopefully, many more to come, and with this team, hopefully a lot more success.”

“I don’t know if I felt really anything different. It was just kind of a confidence thing,” said Keller. “I know I belong here, and I know I can do it. It’s just a mindset of, ‘Here’s my best stuff. Try and hit it.’”

It helped that Keller had a lead to work with before even setting foot on the mound, with his teammates taking advantage of some sloppy Angels defense to put up a three-spot in the top of the first. It turned out to be all Keller would need.

“Whenever we’re scoring runs is awesome as a starting pitcher, for sure,” said Keller. “Going out there with a three-run lead right off the bat there. It doesn’t change the way I was pitching. I would’ve pitched the same way if it was 0-0 going out there. But, yeah, it’s definitely a good feeling, all the time.” (S Wexler - MLB.com - Aug 13, 2019)

August 27, 2019: The honor was neat and the recognition was appreciated, but Mitch had bigger goals in mind after being named the International League’s Most Valuable Pitcher.

“It’s really cool. Hopefully I’ll get that award up here someday,” Keller said. “It’s cool just to be recognized for all the hard work and everything I’ve done to get myself here. It’s awesome.”

Keller led the Triple-A International League in ERA (3.56) and strikeouts (123) when he was promoted to the Pirates’ rotation on Aug. 12. Overall, he went 7-5 for Indianapolis, while posting a 1.24 WHIP and holding opponents to a .243 batting average over 19 starts.

Keller on how he developed his slider: “When Joe Musgrove came down to Double-A last year [on a rehab assignment], he kind of bounced the cutter-slider idea off me. Before that, I’d never even thought about throwing a slider. We were playing catch. Me and him were throwing partners that day, and he was throwing one. I was like, ‘Dang, that’s a pretty good pitch; I want something like that.’

After we were done, I talked to him and got an idea. So, last off-season, I started trying to throw a cutter. I worked on it in spring training, but I didn’t really have one when I got to [Triple-A] Indianapolis. But I talked to Alex McRae about it — he’s got a really good cutter-slider type of pitch — and I kind of learned it from him, honestly. I probably started throwing one in my second or third start, in Indy. I’ve been using it ever since, although it’s definitely changed. It’s not even close to what it was at first. At the beginning of the year it was kind of like a cutter — it didn’t really have much depth to it — but then I started trying to use it more like a wipeout slider.

“I don’t know if I can really explain how. It’s kind of a feel thing. There’s kind of a mental cue that I have, to get out front and rip it down. I guess that’s what goes through my mind when I think about throwing a really good one. So I still throw it hard [87-92 mph], but it’s a slider. In my mind, a cut fastball has a subtle kind of cut to it, while a slider has more depth. That’s how I use it, as more of a depth pitch.

“Developing it has been kind of trial and error. I bounced grips off of guys, and I’m kind of still working on grips, to be honest. Maybe something here or there will help out a little bit, and it will become more consistent. I have thrown in front of a Rapsodo and an Edgertronic. I used one in the off-season, and we have one here, too. It’s been a big help for me. I like the visual picture of what the ball is doing, what it puts in my brain. I’m a visual learner.” (David Laurila - Fangraphs - November 5, 2019)

In his 2019 rookie season, Mitch had a 7.13 ERA to go with a 3.19 FIP. But in 2020, he had a 2.91 ERA to go with a 6.75 FIP.

2019 Season Pitch Usage: 4-seam Fastball 59.5% of the time, his Change 3.7%; Slider 20.9%; and Curveball 15.9% of the time. Average velocity: 4-seam 95.5 mph, Change 91.2, Slider 87.8, and Curve 81.2 mph.

Keller has a 93-99 mph FASTBALL with excellent late-sinking, generating weak contact or for swinging strikes. Mitch also has a big 12-to-6 CURVEBALL with hard, downer bite that he can vary the speed of. He added a SLIDER early in 2019 because of issues with Keller’s changeup, which flashes average potential with fade, but has largely been inconsistent and ineffective. And he has some feel for his 88-91 mph CHANGEUP that he can locate well.

Even when he was struggling, Keller's pure stuff was plenty good enough. He'll throw his heater with good heavy sink to get ground-ball outs and he'll also miss bats with it. His 11-to-5 power curve is another out pitch for him, but he actually threw his newer slider more once he was in the big leagues and it became a good weapon for him, especially at the end of the 2019 season. He will need to throw his changeup more as he establishes himself, but it's an average off-speed pitch.

Keller has struggled with his command over the last couple of seasons, both in terms getting too much of the strike zone and an increased walk rate, though that was a bit better in 2019 overall. At the end of the year, the quality of strikes was much better, as was his overall execution of his pitches, something the Pirates are confident will carry over to 2020. (Spring 2020)

Mitch's Fastball is 70 grade. His Curve gets a 60, as does his Slider. He has only a 45 on his Changeup. But his Controls is a 60.

Mitch has big stuff and throws strikes, but he often gets too much of the plate and struggles with sequencing. (Tim Williams - BA Prospect Handbook - Spring 2020)

In the minors, Keller recorded a 3.12 ERA and 1.16 WHIP with a 3.33 strikeout-to-walk ratio from 2014-2019. And he did so convincingly enough to consistently register as one of the Top 50 prospects in baseball over the past three years. Amid his struggles in the Majors, he struck out 28.6 percent of the batters he faced and walked only 7 percent.

The 6-foot-2 righthander still has that front-of-the-rotation potential. And he knows it, too. Whenever baseball returns, it's easy to imagine Keller taking a massive step forward just due to better pitch-sequencing and anything less than the catastrophically bad batted-ball luck he endured last season. Working with pitching coach Oscar Marin and bullpen coach Justin Meccage, Keller learned this spring how to make better use of his fastball, slider and curveball.

Simply put, Keller is much better than 2019's numbers would indicate (1-5 record and 7.13 ERA in 11 starts). As he told MLB.com, "Ultimately, one day I want to be the ace, so that's what I'm trying to be right now." (Adam Berry - MLB.com - April 2, 2020)

2020 Improvements: Mitch referred to the past few months as a “second off-season” twice, but the Pirates’ top prospect didn’t actually take much time off.

While baseball was shut down due to the coronavirus pandemic, Keller assigned himself two pitching projects. He wanted to improve his fastball’s spin direction and spin efficiency, and he set out to find an effective changeup. Armed with his own Rapsodo inside an empty facility near his home in Iowa, Keller went to work.

"That was the main point when going back home. We don't want to lose anything that we had gained, because we made some good strides in Spring Training,” Keller said on a Zoom call. “We didn't want this to be a setback. We wanted to be able to use it as a point where I can go forward, and I think I really used this time back home to further my game.”

Keller has worked with the Rapsodo tracking technology before, but he essentially only used it to ensure that his pitches were moving the way they had in previous seasons. But this spring, analytically minded pitching coach Oscar Marin helped Keller understand what the Rapsodo data meant and how he could alter his arsenal to change those numbers for the better.

"Once we left Spring Training to go back home, I had a plan in my mind [of] where I want my numbers to be and what I need them to look like to be successful here,” Keller said.

Keller focused on the spin of his fastball, improving his spin efficiency from the lower 90th percentile to around 95 percent. He’s tinkered with changeup grips and continues to do so, looking for another off-speed pitch that will complement his fastball, slider and curveball. (Adam Berry - July 6, 2020)

Like so many other Pirates pitching prospects, Mitch was instructed in the Minors to pound the bottom of the strike zone with his fastball to produce ground balls. The new staff in Pittsburgh has helped change that, pairing high fastballs with Keller’s hard-breaking slider and swing-and-miss curveball.  (Berry - mlb.com - 9/19/2020)

Sept 25, 2020: Keller ended his season with a hitless streak that evoked statistical comparisons ranging from Johnny Vander Meer to Dock Ellis to Jason Schmidt.

After throwing six hitless innings against the Cardinals, Keller didn’t allow a hit against the Indians over five innings in the Pirates’ 4-3 loss at Progressive Field. According to STATS LLC, Keller became the first National League pitcher to complete back-to-back no-hit outings of at least five innings each since Vander Meer’s consecutive no-hitters on June 11-15, 1938.

“Obviously we’d prefer more strikes, but I think it just shows the quality of his stuff,” Pirates manager Derek Shelton said. “The fact that he ends the season with 11 straight no-hit innings, that’s pretty damn good.” (A Berry - MLB.com - Sept 25, 2020)

2020 Season: Keller entered the season as the top prospect in the organization, a kid coming into his own after a rocky rookie season. And he had high expectations, setting out to become not only a member of the Pirates’ starting rotation but one who would provide quality starts every five days.

Instead, Keller finished with five starts. That several of them were quality was a strong sign for Keller, who spent six weeks on the injured list with a strained left oblique. He earned the victory in a 5-1 win at St. Louis on July 26, the first major-league managerial win for Pirates skipper Derek Shelton.

Keller didn’t get another win, despite a strong finish. He threw 11 consecutive no-hit innings to finish the season, following six scoreless innings in a 5-4 loss to the Cardinals on Sept. 19 by allowing one run (and eight walks) in five innings in a 4-3 loss at Cleveland on Sept. 25.

“The eight walks really sucks. I don’t remember the last time I did that,” Keller said. “At the end of the day, I kept the team in it. I got through five innings with one run. That’s the big thing for me, taking the positive out of that and doing whatever I could to make it through at least five for us.”

Throwing at least five no-hit innings in successive starts is a feat that had been accomplished in the National League only once since 1901, when the Cincinnati Reds’ Johnny Vander Meer threw back-to-back no-hitters in 1938.

“He threw five no-hit innings against a playoff team,” Shelton said. “We’d prefer more strikes, but I think it just shows the quality of the stuff. That’s pretty impressive without your best stuff. The fact that he leaves the season with 11 straight no-hit innings, that’s pretty good.”

In between, Keller had some rocky moments. He allowed more walks (18) than he had strikeouts (16), as his strikeouts per nine innings dropped from 12.2 in 2019 to 6.6 last season while his walks per nine increased from 3.0 to 7.5. He also allowed four home runs. It was in his second start of the season, against the Cubs, that Keller knew something was wrong. He allowed five hits, including two home runs, and a walk in 2 2/3 innings before leaving with discomfort in his side. Keller didn’t make another start until Sept. 14.

“One of the things we’re really happy about, before he had the injury, was how he was progressing,” Pirates pitching coach Oscar Marin said. “In his last start in St. Louis, he didn’t have his best stuff, but he rolled five innings and he limited that offense pretty well. The whole thing about it was, that was him (saying), ‘All right, I don’t have my best stuff today. What’s going to be the challenge today?’ We challenged him to change speeds, change eye levels. He was able to do those things.”

The Pirates identified a problem with Keller and worked with him to maintain his posture down the slope. And they believed that working with Jameson Taillon, who was rehabilitating from a second Tommy John surgery, was the best thing for Keller’s development. He got to pick Taillon’s brain about preparation and pitch sequencing.

“They talk every day, they watch the games together. When certain situations come up during the games, they’re talking about it,” Marin said. “What better influence than having Jamo right there with him? Those are the kind of things that that have helped him out. Every time he’s thrown a bullpen or live BP, we’re talking him through those situations: ‘Hey, what was the thought process behind that pitch? What’s your thought process in the location of this one?’ and then having him understand different things so he can keep growing, even without reps in a game.”

The future: A positive sign for Keller was the effectiveness of his fastball, as he touched 97 mph and was able to locate it for strikes in his six no-hit innings against the Cardinals on Sept. 19.

“He was obviously really good. He just had a really good fastball, maybe the best I’ve seen since I’ve caught him in terms of where he was locating it and the overall life on it, playing up,” Pirates catcher Jacob Stallings said, noting that Keller threw mostly fastball-sliders to righties and fastball-curveballs to lefties. “The fastball was just really working and he was obviously able to use the off-speed stuff to get them off the heater and put ‘em away.”

The Pirates believe that Keller, the organization’s top prospect, has the stuff to become a top-of-the-rotation starter, even if he has only 16 career Major League starts. He has to show more consistency and durability than he has in his first two seasons, but there is hope that the last two starts were a turning point. The Pirates would love nothing more than to have Keller and Taillon at the top of their starting rotation, though both have a lot to prove.

“If I can be a No. 2 behind Mitch Keller, that’s really good for our organization and our team,” Taillon said. “I would happily pencil in behind him.” That almost made Keller blush.

“I’d be happy,” Keller said, “if I was No. 2 behind him.”

The Pirates would be happy to have a No. 1 starter. The sooner Keller can elevate to that role, the better.  (Kevin Gorman - Nov 16, 2020)

June 11, 2021: Keller’s up and down season moved into its third month without any signs of straightening out and trending up yet.

His four-seam fastball has velocity, as he’s able to sit in the mid-90s and touch 98 mph. That kind of heater tends to play in the big leagues, but it’s not been up to par in Keller’s case in terms of production against it, and that’s been largely true even with a sharp drop in weighted on-base average from his rookie season to this season. Of 144 pitchers to throw 750 four-seamers between 2019-2021, Keller has the eighth-highest weighted on-base average (wOBA) off his four-seamer (.410). It was at .499 in 2019, but has dropped to .366 this season. That’s mainly due to a drop in batting average against, but the slugging mark against of .471 has stayed fairly high, as 13 of the 25 hits off the four-seamer have gone for extra bases.

Since Keller relies on his four-seam fastball so much, using it 57.2% of the time on average this season, it’s important that he locate it as well. However, among pitchers who have thrown 750 fastballs in 2021, he has the fourth-worst rate of four-seamers for balls (not including intentional balls) at 21.1%.

The whiff rate on Keller’s slider has been lower than past seasons, but not alarmingly low. However, he’s left 24.4% of his sliders over the heart of the plate, as defined by Baseball Savant, and they’ve gotten hit (.425 wOBA and a .420 expected wOBA).

He’s middle of the pack in whiff rate at 31.4%, which ranks 52nd out of 80 pitchers with 100 swings induced on a slider in 2021. Batters are squaring up his curveball like never before. Keller has the lowest whiff rate this season of any MLB pitcher with 50 swings induced on a curveball at 15.4%, which is 7% back of the next closest pitcher (Jameson Taillon).

In short, his fastball is fast, but fairly straight and not being commanded well, per his own admission and the data. His slider is finding the heart of the plate a quarter of the time, and his second off-speed pitch is being hit at a higher rate than ever before in his MLB career.

Keller, Shelton and Cherington all trust that the work the right-hander and former No. 1 prospect in the organization is doing in the background is pointed toward a good outcome. It’s just been a bumpy road so far for Keller, who has still yet to pitch 30 Major League games.

"I think we have a good plan,” Keller said. “It's just me going out and executing.” (J Crouse - MLB.com - June 11, 2021)

2021 Season: Keller went 3-7 with a 7.04 ERA in 12 outings to start the season, yielding 56 hits and 29 walks while striking out 51 in 47 innings. Manager Derek Shelton and GM Ben Cherington had seen enough and sent Keller back to Indianapolis in mid-June after a short stint on the injured list. In eight appearances, Keller went 1-1 with a 3.21 ERA, and the Pirates recalled him to Pittsburgh at the end of July.

He pitched in 11 games the rest of the way, and things did not get much better; his ERA during that 53 1/3-inning stretch was 5.40 and he gave up 75 hits and 20 walks while striking out 41. Opposing hitters raked at a .350 clip.  (Robert Kelley  Jan 13, 2022)

March 20, 2022: Keller’s viral bullpen session was conducted at Tread Athletics, a private training facility that was introduced to him by former Pirate Clay Holmes. There, Keller had one main goal: re-lengthen his arm action.

Keller had shortened his arm action beginning in 2020. Devin Hayes, a performance coordinator at Tread Athletics who worked extensively with Keller, explained that shorter arm action essentially took away velocity and Keller’s ability to “supinate,” or turn his wrist. The numbers are jarring.

Before Keller shortened his arm action, his average fastball velocity was 95.4 mph. The last two seasons, Keller’s fastball velocity dropped below 94 mph. By re-extending his arm action, Keller would more effectively supinate and utilize his body’s upper half. Those tweaks, in turn, would lead to better stuff . . . and better results.

To achieve that length, Keller frequently performed a figure eight drill to help create fluidity and improve arm path. Keller also did the “Kikuchi Drill,” named after Yusei Kikuchi, which helps with the body’s lower half. To complement all the throwing, Keller went through general strength and conditioning during his week with Tread. Social media soon discovered the fruit of Keller’s labor. (JD Santos - MLB.com - March 20, 2022)

2022 Improvements: Beginning last month (May), Keller has introduced and incorporated a sinker into his arsenal, which is slowly becoming his primary pitch.  (Justice delos Santos)

June 8, 2022: -- The theme of this year in 2022 for Mitch Keller has been change. He modified his arm action in the offseason to rediscover his velocity. He added a “sweeper” to his repertoire. He made his first Major League relief appearance. And in recent weeks, Keller’s pitch profile has been headlined by a new toy.

Beginning last month -n May, Keller has introduced and incorporated a sinker into his arsenal, which is slowly becoming his primary pitch. Keller threw a career-high 42 sinkers as he pitched six innings of one-run ball with seven strikeouts in the Pirates’ 3-1 loss to the Tigers at PNC Park. Keller is still in the experimental phase, but his early returns with the sinker in his bag have been promising. “I think I still don't have all the feel in the world for that pitch yet, but it's just such a good pitch with so much movement that it just gives me the confidence to attack the zone with it, even if I am … missing arm side or missing down with it,” Keller said.

With the caveat that correlation does not imply causation, Keller has thrown the ball well since introducing the sinker on May 18. In his past four outings, Keller has struck out 18 batters across 17 innings with a 2.65 ERA. Other factors have contributed to his success aside from the sinker -- Keller called his two appearances out of the bullpen against the Cubs and Rockies a “reset” -- but the sinker has quickly proven its effectiveness. (JD Santos - MLB.com - June 8, 2022)

Through 39 starts in his first three seasons, Keller was 7-17 with a 6.02 ERA and 1.72 WHIP. He was demoted to Triple-A Indianapolis during the 2021 season, and saw the velocity on his heater drop to 93.8 mph.

As Keller’s velocity dipped, so did his confidence. He worked with Tread Athletics, a North Carolina-based pitching development company that custom-builds throwing programs, and touched 100 mph in the offseason.

Keller’s confidence returned but the results were up and down. He was 0-3 with a 6.62 ERA and 1.64 WHIP in four starts in April and was 0-5 with a 6.61 ERA by May 13.

“I thought I did pretty well in the first month, just some bad luck here and there,” Keller said. “Just seemed like anything was falling through.”

Where that would be devastating to Keller in previous seasons, he simply went back to the lab and reinvented himself. Keller moved to the bullpen for two games, added a sinker to his repertoire and started leaning more on a sweeping slider as his putout pitch.

The change started when Keller allowed two runs on two hits and five walks while striking out five in five innings in a 5-3 win at the Los Angeles Dodgers on May 31.

“Watching Mitch over the last couple years and doing what he’s doing right now, that’s one that hits you heavy in the heart in a good way because you know the struggles that he’s had,” Pirates pitching coach Oscar Marin said. “To be where he’s at right now, it’s a big win for him. We’re really proud of him because of that.

“It wasn’t easy the way he did it, either. Obviously, throughout the offseason he got his power fastball back and came into spring training pretty confident that he did just that. … The work to maintain his stuff where he’s at is huge. We’re really proud of him because of that. He deserves a lot of credit just for sticking with that process to continue to trust when the game asks him to do something. It was asking him to make a change, and he did it.”

Over his final 22 starts, Keller went 4-7 with a 3.22 ERA, 106 strikeouts against 45 walks and allowed nine home runs. He made a dozen quality starts over that stretch, including a 10-strikeout performance in a4-2 win at Milwaukee on Aug. 30 and tossing six scoreless innings in an 8-2 win over the New York Mets on Sept. 6.

“Just proud of myself for how I hung in there and kept going,” Keller said. “I know I’m a good pitcher. I know I’ve done it in the past. Just felt really good after that point.”

What the Pirates were most impressed with Keller is how he handled adversity. Pirates manager Derek Shelton noticed the change in Keller’s outlook, especially how he handled adversity.

“The No. 1 thing that’s jumped out to me is his demeanor,” Shelton said. “Every time he takes the mound, he expects good things to happen. That’s something you have to develop at the major league level. Mitch in the past has been in situations where he may have doubted that something good was going to happen and he had to execute a pitch. Now, he really thinks, ‘All right, I’m in control, I’m gonna go after people.’ That’s definitely a sign of growth. It’s a sign of maturity. It’s a sign of a young player coming into himself. I’m really proud of him for that. It takes mental fortitude to get there and I think we’ve really seen him grow that way this year.”

Where in the past he allowed a bad pitch to turn into a bad inning and a bad outing, Keller pitched with more confidence and conviction and learned how to escape jams.

“Being able to slow the game down has been a huge thing for me,” Keller said. “In the past, when I’d get runners on base I’d get a little flustered and keep thinking about the previous at-bats instead of slowing it down and thinking about the next situation and the next pitch. I think that’s been huge for me, to have success and keep going and to have the outings that I’ve had. To be able to take a deep breath, take a step back and slow things down is really helping me out.”

Keller was voted the winner of the Steve Blass Award as the team’s top pitcher by members of the BBWAA.

The future: Keller led Pirates pitchers in games started, innings pitched and walks, and ranked second in strikeouts.

He couldn’t wait to work on getting better.

When one pitch wasn’t working, Keller wasn’t afraid to rely on something else. He still threw his four-seamer the most (33.1%) but held opponents to a .206 batting average with his slider. No wonder Keller wasn’t ready to call himself a sinkerballer just yet.

“I’m still trying to find my way. It’s definitely been a growth period for me this season, just finding who I am as a pitcher and where the game’s at and where the hitters are at,” Keller said. “My four-seamer wasn’t playing like I’d hoped it would so we needed to adjust. I think adding the sinker and adding the sweeping slider has helped me develop. It’s a new arsenal, really. To be able to use that in games and do well with it has been a huge confidence booster for me.”

Keller headed into the offseason with the confidence to know that he belongs in a major league starting rotation. Where he went searching for solutions last year, he intended to make tweaks this time. He hopes to develop into an anchor and finally live up to his top-prospect status.

“I can really get to work on some other things rather than just trying to get velo back and trying to throw hard,” Keller said. “I feel like I can be the guy. I’m not going to put that on myself or anything like that. It just comes naturally to a clubhouse and to a team. I feel confident in my abilities.”  (KEVIN GORMAN   | Wednesday, Nov. 23, 2022)

April 1-Aug 2, 2015: Keller had a bout of forearm soreness, an injury that usually is a precursor to Tommy John surgery. But he endeavored to alleviate the problem via conditioning workouts. (He also missed 5 weeks in May and June with a back sprain.)

Aug 2017: Mitch overcame a back strain to earn a promotion to Double-A Altoona.

Aug 2-Sept 14, 2020: Mitch was on the IL with left side discomfort.