Speier grew up in California. His dad's uncle is Chris Speier. 

Gabe's family has a deep baseball history. His dad's uncle is Chris Speier, a big league shortstop from 1971 through 1989. Chris's son, Justin Speier, was a pitcher in the majors from 1998 through 2009.

So, there has been a Speier in the majors during every decade from the 1970's, 1980's, 1990's, 2000's, 2010's and 2020's -- six straight decades.

Most Indispensable 'Under-the-Radar' Player: Gabe Speier, Mariners.

President of baseball operations Jerry Dipoto: “Among (our under-the-radar players) who get very little fanfare is Speier, who deserves to be noticed. He’s been awesome from day one, lives in high leverage and has been incredibly consistent, and until very recently, was doing it as the lone lefty in the pen.” (Bowden - Aug 22, 2025 - The Athletic)

Jan 14, 2026:  USA Baseball announced the addition of left-hander Gabe Speier of the Mariners. 

TRANSACTIONS

June 2013: Speier was the Red Sox 19th round pick, out of Dos Pueblos High School in Goleta, California. 

December 11, 2014: The Tigers traded RHP Rick Porcello to the Red Sox for LF Yoenis Cespedes, RHP Alex Wilson and LHP Gabe Speier.

December 9, 2015: The Braves traded RHP Shelby Miller and LHP Gabe Speier to the Diamondbacks; acquiring OF Ender Inciarte, RHP Aaron Blair, and SS Dansby Swanson.

June 6, 2018: The Royals acquired Speier from the D-Backs.

Nov 9, 2022: The Mariners claimed LHP Gabe Speier off waivers from the Royals.

Jan 9, 2025: Gabe and the Mariners avoided arbitration, agreeing to a one-year deal worth $845,000.

Speier is a lefthander with a 90-94 mph FASTBALL and a SLIDER.

2019 Season Pitch Usage: 4-seam Fastball 60.8% of the time; his Sinker less than 1%; Change 2%; and Slider 36.6% of the time. Average velocity: 4-seam 94.6 mph, Sinker 87.5, Change 85.8, and Slider 82.6 mph.

Those numbers gave Speier one of his best professional campaigns and spurred the Royals to summon him to Kansas City again; and this time, Speier flourished. He appeared 7 times after his Sept. 15 callup, giving up only one run in 7.2 innings for a much-improved 1.17 ERA, and didn’t walk a single batter. (Mike Gillespie - Oct. 21, 2021)

2023 Season: The Mariners claimed the lefty from the Royals on Nov 9, 2022, in an under the radar move. The 28-year-old had thrown a career 40 innings over 4 seasons with the Royals with a 3.83 ERA, 3.4 BB/9 and 7.9 K/9. Those are pretty unspectacular numbers, but as with any reliever the Mariners acquire, you sort of wondered what kind of arm he might develop into, given their history of turning relievers careers around.

Gabe Speier started the year, pretty good, but not anything too crazy. In April he threw 11 and 1/3 scoreless innings which is impressive but only struck out 8 while walking just 1 batter. A rough May and June had many wondering if they needed to look elsewhere for an arm.

But for the months of July, August and September, he was absolutely dominant and showed his true potential. During those 3 months he threw 26 innings with a 3.47 ERA, but where showed his upside was on his strikeout numbers. In those 3 months, he struck out batters at a rate of 12.81 K/9, showing his potential to be a very valuable late-inning reliever.

Speier was a waiver claim with a whopping 40 innings pitched. He showed what he can become in the right situation and opportunity and he made the most of it. He guaranteed himself a spot in the 2024 bullpen, as a solid arm that can get you some big outs when needed. He had some rough spots throughout the year which is why I couldn't bump it to an A- but given the fact that he was just a waiver claim, he was more than worth it. Plus, his newfound confidence and "screw it" mentality made him very entertaining and something this bullpen was lacking.

Speier is still pre-arbitration eligible, meaning there are a lot of years of control there for him. As we all know, relievers careers are very up and down and hard to predict. Much is probably the same here, but I think there is potential that Speier becomes a key part of this bullpen given his controllability and minimal salary.

That paired with his elite strikeout numbers and minimal walks, means he fits right in with what the Mariners want with their bullpen arms. He spoke to Ryan Divish on his increased confidence level and how his change in mentality has taken that next step in career. I expect a few teams to reach out the Mariners this offseason in regard to Speier, but he is more valuable for what he is in your bullpen than what he might fetch you in a trade.

Plus, he has shown an ability to get out the biggest pain in the butt for Mariners fans that is Yordan Alvarez. Alvarez went 0 for 4 in 2023 against Speier with 2 strikeouts, none bigger than the one on August 20, en route to a 3-game sweep of the Astros. (Tanner Vogt - Oct. 13, 2023)

2024 Season: Per MLB Statcast data, of the 422 pitches he threw at the MLB level last season, he threw six pitches that registered at 95 mph or faster. He threw another 14 pitches between 94.5 and 94.9.

By comparison, Speier threw 782 pitches in his breakout 2023 season with 224 pitches at 95 mph and 74 more pitches at between 94.5 and 94.9. His four-seam fastball averaged 95.1 and his sinker averaged 94.4.

But a few weeks into the 2024 season, something just didn’t feel right with his arm. It started on a hellacious road trip to the East Coast that Speier said, “beat me up a little bit.”

All 20 of those pitches that registered 94.5 mph or faster came in his first 22 appearances of last season. Speier went on the injured list with a left rotator cuff strain on June 1. He had also suffered a partial tear of his subscapularis. Speier received multiple injections, including platelet rich plasma, in hopes of speeding up his recovery and getting back to full strength. While he would eventually return to the Mariners bullpen on July 19, the velocity and life on his pitches did not.

“I was trying to throw hard,” he said. “It just felt like my arm was dead after the injury. I just never got my footing back.”

It affected his mindset on the mound. He started chasing after velocity, knowing it helped him be effective. But as he tried to generate those few ticks of velocity, his command, which had been stellar in 2023, started to wane. He walked 13.5% of the batters he faced, which was almost triple the 5.1% he walked in 2023.

“That was a thing for me last year,” he said. “Everyone wants to throw hard, and I’ve shown that I can throw hard, and then all of a sudden, I’m not. It was definitely something I was chasing instead of maybe locking in on the zone and trying to pound the zone. I was just trying to throw the ball hard. So, my intent wasn’t quite what it should have been. So not only was I not throwing the ball hard, I wasn’t commanding it either.”

The Mariners eventually sent Speier down to Triple-A Tacoma due to ineffectiveness.

“It was definitely frustrating,” he said. “You never want to get sent down to Triple-A, and unfortunately that happened.”

But he has no plans of it happening again.

With the help of Trent Blank, the Mariners director of pitching strategy, Speier worked out a training and throwing program for the offseason. He postponed a family vacation to Hawaii and chose to focus on getting stronger in the weight room and building arm strength by throwing.  

“Really, I didn’t put the ball down,” Speier said. “As soon as I got home, I was still throwing three days a week. I didn’t stop throwing. I just kept getting my arm going with lots of long toss.”

In the weight room, Speier did hours of power strength training, moving heavy weight faster than he’d ever done before. There were dead lifts until his legs felt weary.

“I started to feel powerful and like an athlete again,” Speier said. “The ball started zipping out of my hand in the offseason and it still feels the same now.”

If Speier can return to his form of 2023, when he produced a 78.2 first-pitch strike percentage with 5.82 strikeouts for every walk and held left-handed hitters to a .218 batting average and .534 on-base plus slugging percentage, the Mariners bullpen will solidify a key role in late innings.

A bounce-back season from Speier and healthy seasons from Matt Brash and Gregory Santos will play a huge part in any overall success for the Mariners this season.

“Obviously, staying healthy is the No. 1 thing,” Speier said. “And if all of us can do that, we will have a really, really good bullpen.” (Ryan Divish: rdivish@seattletimes.com. - Feb. 17, 2025)

2025 Season: Is Gabe Speier a lefty? Yes. Is he a reliever? Yes. Is he good? Yes. And yet, to describe him as a good lefty reliever is a disservice. There’s something about describing someone as a lefty reliever that feels caveated. It always reads as implying that a pitcher is only good “for a lefty” or that he’s a special-use weapon who can be called upon to get lefties but needs to be pulled before he loses his natural advantage.

What I mean is perhaps best demonstrated through a couple counterexamples: Josh Hader and Aroldis Chapman. Are they lefties? Yes. Are they relievers? Yes. Are they good? Yes. But you wouldn’t really call them “good lefty relievers.” They’re just good relievers. (There are also plenty of other things you could call those two, but I digress.) Speier’s probably not as good as either of them, and he’s only been great in two years, interrupted by an injury year, rather than a whole career. But at this point, Speier has pitched well enough for long enough to at least be talked about more like them than like a glorified LOOGY.

So it rankles that after being deeply underrated, Speier finally stepped into the national spotlight this October only to have essentially all the conversation revolve around his status as a lefty. Most prominently, we were treated to a weeklong debate about how the Mariners could survive Kerry Carpenter. But Speier is no specialist, and while it’s nice that at least he has a reputation at all now, that reputation ignores the changes he’s made to become one of the game’s very best relievers, full stop.

If you really insist on the lefty qualifier, you’d have to describe him as elite, not just good. 362 pitchers threw at least 20 innings against lefties last year. Gabe Speier had a strikeout-to-walk ratio of 21-to-1; only one of the other 361 pitchers was better, and that guy just won his second consecutive Cy Young. I’m not going to belabor the point: If all Gabe Speier amounted to was a lefty specialist, you’d have to say he’s at the top of the heap. And while he was less effective as he played through injury in 2024, this is consistent with his results from 2023.

But he took a big step forward in 2025 by improving his attack against righties. In 2023, 206 relievers threw at least 750 pitches, at least 100 of which were to right-handed batters. (I used some uncommon thresholds to create the right sample because it was hard to get the data I wanted while using an IP minimum, but please bear with me while I continue to learn to code. Maybe if you bug him, Ryan will tutor me. The important thing here is that the sample of pitchers I’m using here is ultimately the correct pitchers if you look at the names.) Speier struck out 30.5% of the righties he faced, while walking 6.9% of them. That’s a strikeout-rate-minus-walk-rate of 23.6%, which is good by any standard. It ranks 31st out of the 206 relievers in the sample. In other words, on his weak side, Speier is better than 85% of his peers. And among the 30 pitchers ahead of him, Speier’s .340 xwOBAcon was in the top half, so it’s not like he was giving this all back by surrendering loud contact.

If all Speier did last year was face right-handed hitters, while everyone else faced both righties and lefties, Speier’s FIP would have been in the 93rd percentile, two spots behind Andrés Muñoz and two spots ahead of Griffin Jax. No doubt, Speier is better against southpaws than northpaws, but this is a strength and a strength-that’s-a-little-weaker, not a strength and a weakness. David Bowie was a better singer/songwriter than actor, but have you seen Labyrinth?

Gabe Speier is back and better than ever. Without going in depth, the big change Speier made is hardly difficult to identify: facing righties this year, he cut his sinker rate in half and his slider rate by a third, which allowed him to essentially double his four-seam usage. It’s just another case of a Mariners' reliever identifying a pitch that works and using it more often.

Put together his elite stats against lefties and his still quite good stats against righties and Speier’s 2025 resulted in a FIP- of 57, which was 15th among the 325 relievers who pitched at least 20 innings. Breaking out the most important pieces of FIP, his K%-BB% was fourth, in a top five that also includes Mason Miller and Edwin Díaz as well as, what do you know, Hader and Chapman. That’s not a good lefty reliever, but simply one of the game’s best bullpen arms.

To be sure, the centrality of his handedness in October’s national conversation had more to do with how Dan Wilson was going to manage the pitching staff as a whole to get tough lefties out than it did with Speier’s talents. But the focus still sold Speier short. That was predictable: If there’s been a theme in my writing about Speier, it’s been that he’s underappreciated. I used his 2024 40 in 40 to urge you to join his fan club, which of course you did, and earlier this year, I pitched his case to make the All-Star team, which of course he didn’t.

But at least there’s a national conversation about him at all. Justin Klugh put the sentiment well when previewing the ALDS for Baseball Prospectus: “A guy named Gabe is also one of the best relievers in baseball, apparently.” That reflects Speier being underappreciated but it’s a long way from Jeff Sullivan’s only Speier reference in his 1,500-word write-up of the Shelby Miller trade: “Arizona also got Gabe Speier, who is a player.”

If Speier repeats his 2025, it’ll be the third year out of four in which he performs as one of the game’s best relievers. At some point, people will have no choice but to notice.  (Zach Mason - Dec 31, 2025 - Lookout Landing)

July 2013: One month after getting drafted, Speier had Tommy John surgery after making only three appearances in the Rookie-level Gulf Coast League. He returned a year later.

July 5, 2016: Gabe was on the D.L.

May 30-June 17, 2022: Gabe was on the IL.

May 30-July 19, 2024: Gabe was on the IL with left rotator cuff strain.