Diaz was born in Puerto Rico and moved to the U.S. when he was 4.

Isan gets compared to former Puerto Rican big leaguer Jose Vidro.

In 2014, Diaz got drafted by the D-backs (see Transactions below).

Regarded as a bat-first middle infielder during his high school days, he showed the opposite traits in his debut in the Rookie-level Arizona League in 2014. Diaz played a better-than-expected shortstop but struggled with the bat. He looked better in Instructional League, and scouts believe the bat will come around because he has good hands.

In 2015, Diaz was the Pioneer League MVP after leading the loop in multiple hitting categories.

In 2015, the Baseball America Prospect Handbook rated Diaz as 27th best prospect in the Diamondbacks organization. Then he was moved all the way up to #9 in the off-season before 2016 spring training (and just before Isan was traded to the Brewers organization).

In 2017, they had Isan at 5th-best in the Brewers farm system. And he was at #9 a year later, early in 2018.

After going to the Marlins organization, Diaz was at #8 in the spring of 2019.

In 2016, Diaz was the Brewers Minor League Player of the Year. Isan spent his first season in the Brewers organization at Class A Wisconsin, hitting .264/.358/.469 with 34 doubles, five triples, a MWL-leading 20 home runs, 75 RBIs, 72 walks and 11 stolen bases. He led the organization in games (135), doubles, home runs and RBIs, and was second in hits (134) and walks.

Isan's poor 2017 season got to him a bit. His frustrations often showed, resulting in some bad body language and failure to run balls out.

2018 Spring Training

MLB Pipeline: You recently got reassigned from your first big league camp. What was experiencing that for the first time like?

Diaz: It was good. It was a great experience for me. I think the most important part of big league camp, and the one thing I grasped on more was going in and not being afraid to make a mistake. My first game, I was a little bit antsy, the game was too fast. A bunch of guys pulled me aside and told me to relax, just take it all in. There are a lot of things you have to hold yourself accountable for. It's a different atmosphere. You want to make a good first impression. I learned a lot. A lot of good veterans up there—Prado, Castro, Miggy [Miguel Rojas]. All those guys helped me for the time I was there.

MLB Pipeline: You had been through a trade before, so at least you knew how to deal with that. When you were traded from the Brewers to the Marlins, did it help that it was your second rodeo, so to speak?

Diaz: Going back to the first time I was traded, that was kind of strange for me. I wasn't aware of anything. This one, I was more into it, I kind of had a little more of an idea of what was going on. I was mentally prepared for this one. It was less of a rodeo, I would say. It was smoother, the transition was easier. Being here now with the Marlins has been great so far. 

MLB Pipeline: Did coming over with several guys help at all? Did a guy like Monte Harrison, who hadn't been traded before, come to you to ask how to handle things?

Diaz: They had some questions and I helped them out. Lewis Brinson is another guy who's been traded twice, so he had intel as well. We spoke to him and told him to just be himself and go out and play. Monte, he's a good guy, he knows how to take care of himself and adapt really fast. 

MLB Pipeline: Looking back at your 2017 season, things didn't go as well for you as it had previously in your career. What happened and what did you take away from it?

Diaz: Last year, the most important part was the mental side of the game. It was very hard, I felt like I was getting beat down every day. It was a learning process, one that I've never been through before. Now I know how to handle certain situations and how to get out of certain slumps. I'm trying to put last year away a little bit and not remember too many parts of it. I'm trying to take the good parts and bring it over to next year.

MLB Pipeline: A lot of people have described that sort of thing as a snowball effect and you feel that you need to get eight hits every at-bat to get out of a slump. Could you feel yourself trying to do too much?

Diaz: It happens, especially when you have a stretch with constant rollovers and strikeouts. Those get very frustrating. You have to figure out a way to get out of it and stay positive and compete. That's the most important part, always competing and trying to win no matter how your day is going.

MLB Pipeline: You were born in Puerto Rico. How much was your family affected by the hurricane?

Diaz: I believe, even if you don't have family members who live there, I think everyone who is from there or has some relation with the island, I think it affects everybody. It was a tragic moment, a time when a lot of us tried to come together and see if we could do whatever we can to help out. It was a moment we take and we grasp onto to make us stronger. It was a very hard time for us, especially for us guys who play in the Minor Leagues. Now, we're trying to take it over to this season and play for them. We try to use it as motivation.

MLB Pipeline: Do you typically go back there during the offseason? I know you grew up in Massachusetts and went to high school there, not Puerto Rico.

Diaz: I'll go home to Massachusetts in the offseason. Then me and the family will take a trip and go visit some family members out in Puerto Rico. We'll do a month out there and see how everybody's doing and enjoy the island as much as possible. A lot of people ask me what made me move out there, what made you move to the cold weather. Honestly, to this day, I don't know what happened. I wish we could've stayed in Puerto Rico, but it didn't happen. I plan on going back this offseason as well, just trying to stay out there and help out. I was around three or four when we moved, I didn't really know much. I'm pretty sure if I were a little older, we probably would've stayed in Puerto Rico. They would've heard me.

MLB Pipeline: I guess the good thing is when you had to go and play in cold weather, like in the Midwest League, you were ready for it.

Diaz: Man, that's tough. It's one of the tougher things to do, is hit in cold weather. But you get used to it after being in it for so long. (Jonathan Mayo - MLB Pipeline - March 2018)

The first time Isan was dealt, from the Diamondbacks to the Brewers before the 2016 season, he was blindsided.

“I was in a movie theater, watching ‘Collateral Beauty’ with my family,” Diaz said. “I got a call from a number I didn’t recognize, and it was Milwaukee’s general manager (David Stearns).”

The second time Diaz was traded was this past Jan. 25, 2018. The Marlins sent outfielder Christian Yelich to the Brewers for four prospects, including three ranked among Milwaukee’s top 10: No. 1 Lewis Brinson, No. 5 Monte Harrison and No. 9 Diaz.

This time, a more mature Diaz was anticipating a trade. He was watching MLB Network on Dec. 7, when the Marlins traded Dee Gordon and remembered thinking: “I could be a part of (the Marlins).”

A little more than one month later, he was, and he now believes his future is becoming clearer.

Diaz, a native of Puerto Rico, moved with his family to Springfield, Mass., when he was 4. Rather than root for the local Red Sox, Diaz—a shortstop growing up—grew up a Yankees fan, idolizing Derek Jeter.

Now, of course, Jeter runs the Marlins as chief executive officer. “When you first meet him,” Diaz said, “you go, ‘Wow! That’s Derek Jeter!’“

Jan 9, 2019:It's no mystery the Marlins are in the market for an impactful lefthanded hitter, and the organization just might have a secret weapon lurking in its farm system. Isan Diaz made big strides at the Double-A and Triple-A levels in 2018, and he wrapped up his year by playing winter ball in Puerto Rico. The 22-year-old is ranked by MLB Pipeline as Miami's No. 9 prospect, and the No. 4 second-base prospect overall. Of all the Marlins' prospects, Diaz is regarded as the closest to being big league ready.

The Marlins consider Diaz their second baseman of the future, and his estimated time of arrival in the big leagues could hinge on how much longer Starlin Castro remains with the organization.  (J Frisaro - MLB.com - Jan 9, 2019)

July 2019: Diaz represented the Marlins at the Futures All-Star Game.

2019 season: A Diamondbacks supplemental second-round pick in 2014 who later was included in trades for Jean Segura and Christian Yelich, Diaz struggled at the plate for two seasons after advancing to high Class A in 2017. He broke out this season, hitting .305/.395/.578 with 26 homers in 102 Triple-A games to claim the second-base job in Miami. Diaz was also named MVP for New Orleans.

Diaz was born in Puerto Rico and moved to Springfield, Mass., with his family at age 4. He grew up a Yankees fan who idolized Derek Jeter. Now, of course, Jeter runs the Marlins.

"When you first meet him,” said Diaz, who turned down Vanderbilt to sign a pro contract out of high school, "you go, ‘Wow! That’s Derek Jeter!’ It’s exciting.” (Walter Villa - Baseball America - Oct., 2019)

Not since Dan Uggla blasted 154 home runs from 2006-2010 have the Marlins had a second baseman with as much power potential as Isan Diaz. The 23-year-old raised his profile after tearing up Triple-A New Orleans, belting 26 home runs with 70 RBIs, and earning a spot in the starting lineup at the Sirius XM Futures Game.

Díaz made his MLB debut on Aug. 5, 2019 and he had almost two full months to get acquainted to the big leagues. The results were spotty. In 49 games, he hit .173/.259/.307 with five home runs and 23 RBIs.

“A lot of learning,” Díaz said. “I had a blast. This is everything I expected it to be. Now I know what I have to get better at. What I have to be more prepared for, and for sure, next year I’m going to come into 2010 Spring Training 100 percent better, for sure.” 

What went right

Díaz made major strides at Triple-A, batting .305/.395/.578 in 102 games, forcing the organization’s hand to reward him with his first MLB promotion.

Even though he had his struggles with the Marlins, the potential is there for him to become a big league regular. He flashed power and had a knack for driving in runs.

“He’s got some work to do,” manager Don Mattingly said. “But what I’ve always liked has been, he sees the ball well. He’s capable of using the whole field, and he has a good swing. He has the attributes, everything is there to allow him to be successful, if he will settle down and actually use the whole field.”

What went wrong

Even after dominating at the Triple-A level, Díaz endured his share of growing pains after being called up. He had his struggles at the plate and in the field. His strikeout rate was 29.4 percent, and he committed nine errors.

Mattingly noted that Díaz often was pull happy at the plate, aiming to drive the ball to right field, to maximize his power. Pitchers exploited his aggressiveness by giving him a steady diet of off-speed and breaking pitches. Per Statcast, Díaz hit .158 off breaking balls with a 45.2 percent strikeout rate. And against all off-speed pitches, he hit .091 with a 46.7 percent strikeout rate.

“I think it’s going to be valuable for him,” Mattingly said of the learning experiences. “He’s at least in a position where he’s got some experience.” 

Best moment

Just making his Major League debut was special. For Díaz, the day was even more memorable because he shared it with his parents at Citi Field against the Mets.

And when Díaz delivered his first big league hit, a home run off Jacob deGrom, his dad, Raul, actually stole the moment.

Raul was being interviewed by Fox Sports Florida during his son’s third at-bat. Moments later, Isan connected on a home run, tracked by Statcast at 422 feet. Raul went wild on air, providing a moment that made national news.

“Obviously, this was his dream, as well,” Isan told reporters after the game. “I’m happy that I was able to finally be able to make our dream come true.” 

2020 outlook

Considering the fanfare Díaz received in 2019, especially after his strong Triple-A season, Marlins fans widely believe he is a lock to be the starting second baseman on Opening Day.

That’s not necessarily the case. He will have to earn it.

“When he comes to Spring Training, he’s going to have to fight for a job,” Mattingly said on the last day of the season. “Obviously, he hasn’t come here and knocked the door down and blew the house up and said, ‘I’m your second baseman!’''

The Marlins may seek a fallback veteran option in free agency, just in case Díaz isn’t ready play regularly. He still has Minor League options.

“He did some things that were really good,” Mattingly said. “He’s had some areas where he’s struggled. So, he’s going to have that experience to go into the winter, and he’s going to have to fight for a job.” (J Frisaro - MLB.com - Oct 25, 2019)

July 31, 2020: Miami placed Díaz on MLB’s restricted list, because the 24-year-old informed the club that he was electing not to play due to health concerns, as well as family reasons.

2020 Season: Díaz got his second taste of the Majors as the Opening Day second baseman, but he elected to opt out when the Marlins experienced a COVID-19 outbreak. After the former top-100 prospect decided to return in early September, he strained his left groin, ending his season after just seven games.

2022 Season: Still just 26, Díaz made a positive impression after being traded to San Francisco on April 30. The infielder compiled a .951 OPS, 23 long balls and drove in 61 runs in 87 games for Sacramento. After spending the majority of 2021 in the Majors with the Marlins, Díaz did not earn a call to The Show this past season. Once a top prospect in the Arizona, Milwaukee and Miami systems, the 2014 Draft pick has yet to enjoy the same success in the Majors as he has in the Minors, where he sports an .838 OPS in more than 2,500 at-bats.  (Michael Avallone - Dec. 12, 2022)

TRANSACTIONS

June 2014: Isan was drafted by the D-backs with their Compensation Round B pick, out of Springfield Central H.S. in Massachusetts. He had committed to play at Vanderbilt. 

He signed with scout Mike Serbalik for for $750,000, below the slot of $804,600.

January 30, 2016: The Diamondbacks acquired SS Jean Segura and RHP Tyler Wagner from the Brewers; sending RHP Chase Anderson, INF Aaron Hill, and SS Isan Diaz and cash to Milwaukee.

January 25, 2018: The Brewers sent OF Lewis Brinson, SS Isan Diaz, OF Monte Harrison and RHP Jordan Yamamoto to the Marlins; acquiring OF Christian Yelich.

April 30, 2022: The Marlins traded Diaz to the Giants for cash.

Diaz has impressive bat speed and great hand-eye coordination. He is strong with a fluid lefthanded stroke, plus bat speed that provides hard line shots to all parts of the yard. He has a natural lift in his lefthanded swing.

Though he looks smaller than his listed 5-foot-10 and 185 pounds, his power grades as at least average and plays in games. And he drives the ball to all parts of the ballpark. Diaz is at least an average hitter with a willingness to hit the ball the other way, and his strikeout (26 percent) and walk rates (13 percent, both in 2018) have remained relatively consistent.

Isan has a 50 hit tool, and 50 power. (Spring, 2019)

Isan exhibits an amazing feel for the barrel, and has a natural easy swing. He struggles with off-speed stuff but has a strong lower half and projects to have average power if it all clicks. His batting stance reminds some of Robinson Cano.

He walks a lot, displaying impressive discipline at the plate. But with his power comes the strikeouts. He can be too aggressive at the plate.

Before the 2015 season, Diaz made a mechanical adjustment that gave his swing more leverage.

And in 2016, he ed the Midwest League on home runs (20). So Isan settled in at the plate and, in particular, found his power stroke,

Diaz has an uncanny ability to find the barrel, making hard contact consistently.

Isan is very confident. He already thinks he's a big leaguer, and that is a good thing.

2016 (batting improvements): Isan Diaz.   1st half: .232/.309/.370  -  2nd half: .296/.404/.569

Diaz started off extremely slowly, hitting just .212 over the season's first two months. Then he hit .316 with a .972 OPS in June, and he put up a .327/.413/.645 line in July. Diaz ended up with 14 homers and a .973 OPS in the second half. His 20 homers for the season actually led the Midwest League, as did his 238 total bases, more than Cubs breakout prospect Eloy Jimenez.

Jan 9, 2019: In 119 Minor League games in 2018, his slash line was .232/.340/.399 with 23 doubles, five triples, 13 homers and 56 RBIs. At Double-A, his numbers were .245/.365/.418 with 19 doubles, one triple, 10 homers and 42 RBIs. There were some growing pains at New Orleans, where his slash line was .204/.281/.358 with three homers and 14 RBIs in 36 games.

In Diaz, the Marlins feel they have a second baseman with 20-homer power, and he has shown the ability to hit the ball hard to all fields. According to Miami's internal analytics, 9 percent of the balls Diaz put in play in the Minors in 2018 had an exit velocity of at least 105 mph. The MLB average is 7 percent. More than just the numbers, the Marlins didn't hesitate to expose Diaz to higher-level pitching, and he saw more of it in the offseason.

When you add in 33 games in the Puerto Rican Winter League, Diaz appeared in 152 total contests, with 545 combined at-bats. That gave Diaz a sampling of what the rigors would be like over a full Major League season. Additionally, Diaz participated in a tournament with the Puerto Rican national team. (J Frisaro - MLB.com - Jan 9, 2019)

With his hand-eye coordination and patience, Isan is equipped to be at least a solid hitter from the left side of the plate, but he owns just a career .263 average in six minor league pro seasons. He does have an aggressive, pull-happy approach and he works deep counts, which leads to strikeouts. He hasn't exhibited much of a platoon disadvantage in the upper levels of the Minors.

Power: Diaz's best tool is his plus raw power, the product of bat speed and the strength in his compact 5-foot-10, 185 pound frame. He's capable of driving the ball out of the park to all fields, though the majority of his home runs come to his pull side. After having an uppercut in his swing earlier in his career, he has flattened his stroke in recent years and become more of a ground-ball hitter without compromising his home run production. He has 88 homers and a .467 slugging percentage in 583 Minor League games.  (Callas - mlb.com - 8/4/19)

August 5, 2019: Marlins infielder Isan Diaz had a day he will never forget. He showed why he's one of the top prospects in baseball. In the sixth inning of the first game of a doubleheader against Mets ace Jacob deGrom, Diaz homered for the first hit of his big league career.

Craig Minervini of Fox Sports Florida was doing a live TV interview on Aug. 5 with the family of second baseman Isan Diaz when the crack of the bat interrupted everything.

The 23-year-old Diaz, making his major league debut against the host Mets, had been hitless in his first two at-bats. Then, in his third try against Jacob deGrom, Diaz pulled a 1-2 fastball over the right field wall. Isan sent the 97 mph fastball 422 feet, and his father’s emotions soared even further.

"Ohhhhhhh . . . ohhhhh . . . ohhhhh,” Raul Diaz yelled excitedly into the microphone.

Later, when Raul Diaz had calmed down, he told Minervini the following: "We just homered off deGrom!”

It was a shocking debut for Diaz because he got to deGrom during a stretch in which the reigning Cy Young Award winner had retired 15 of 16 batters. Diaz’s homer was the only blemish.

Nov 27, 2019: A breakout 2019 season at Triple-A New Orleans made Isan Díaz one of the top prospects in baseball. The left-handed-hitting second baseman belted 26 home runs in the Minor Leagues, and his standout performance propelled him onto MLB Pipeline’s Top 100 list.

Díaz was a starter in the Sirius XM Futures Game in Cleveland, where he caught evaluators’ attention with the way he impacted the ball in batting practice. The Marlins promoted the 23-year-old on Aug. 5, and in his Major League debut, Díaz’s first big league hit was a home run off two-time National League Cy Young Award winner Jacob deGrom.

At the time, Díaz ranked as Miami’s No. 5 prospect (No. 86 overall), according to MLB Pipeline. Díaz is one of the young core players in a deep Marlins system, and he is considered the second baseman of the future. Still, Díaz is taking nothing for granted.

“I’ve got a job to win,” Díaz said. “I’m going into Spring Training with the mentality to win a job, and to work hard every day, and to continue grinding.”

The starting job appears to be his, especially now that Starlin Castro, who moved to third base to make room for Díaz, is now a free agent. Still, Díaz has to show he is ready. Díaz plans to play winter ball in Puerto Rico before Spring Training 2020.

Until Díaz starts playing in games, he has been staying in shape and working out at the Roger Dean Chevrolet Stadium complex in Jupiter, Fla. He’s working with the Marlins’ trainers and taking batting practice with teammates like Lewis Brinson and Miguel Rojas. Díaz was one of a handful of Marlins players to participate in the organization’s annual turkey distribution at Marlins Park.

“It’s great,” Díaz said at the event. “It’s something new for me to be out here, giving turkeys out and seeing everyone smiling and just enjoying the day. It’s really awesome.”

After getting a taste of the big leagues in 2019, Díaz is focused on doing what it takes to establish himself as a regular. Even after Díaz dominated at Triple-A, he had his struggles in 49 games with the Marlins, batting .173/.259/.307 with five home runs and 23 RBIs. He had a 29.4 percent strikeout rate and a 9.5 walk percentage.

The adjustments to MLB pitching didn’t come as easily as it did for Díaz at New Orleans, where he had a slash line of .305/.395/.578 with 26 home runs and 70 RBIs in 102 games. A year ago, playing winter ball helped Díaz get ready for 2019. More than statistics, he was able to see live pitching, logging 114 at-bats in 33 games in Puerto Rico.

“Last year, I did two months in Puerto Rico,” Díaz said. “I think that really had a lot to do with my readiness coming into a Triple-A season. So coming into this year now, I’m trying to repeat the same things and actually add more than I had last year. “It’s going to help me out a lot. Seeing the live pitching is going to help me out most of all.” (J Frisaro - MLB.com - Nov 27, 2019)

Isan has smooth actions, athleticism and tremendous body control. That allows for good range and impressive footwork. He can play a few positions, but second base is his best defensive spot.

Isan's arm is loose and he can throw from different angles. It rates a 50 grade on the 20-80 scouting scale, as does his fielding.

While he spent time at shortstop in 2014 and 2015, Diaz's future is at second base. He could be an above-average defender as well as being able to handle shortstop in a utility role.

However, his defense has become solid, showing the first-step quickness and average arm that is getting better, growing from a 50 to a 55, with 60 future on the 20-80 scouting scale. He competes every single game.

In 2016, Diaz saw most of his action at shortstop in the first half but started playing more at second base, his likely position in the Majors. You don’t see many middle infielders his size with that kind of pop, so he has a chance to be a special offensive player at second base.

He is considered an average defender at short and perhaps a tick above-average at second. His average arm plays better on the right side. (Spring, 2017)

Arm: Like most second basemen, Isan has ordinary arm strength. That limits his usefulness on the left side of the infield. And although he played a good deal of shortstop early in his career, he hasn't appeared in a Minor League game there since June 2017.

Field: He won't win any Gold Gloves, but Diaz is a reliable defender with average range at second base. The majority of his value will come from his bat. If he can realize his 25-homer potential, that will be more than enough to make him a regular. (Callas - mlb.com - 8/4/19)

Isan is an above-average 55 grade runner who won't steal a lot of bases, especially as he grows bigger and perhaps becomes a 50 on the 20-80 scouting scale.

But Diaz gets good jumps on the bases and is an intelligent baserunner, displaying solid instincts.

Isan has average speed and good instincts on the bases. He's not much of base-stealer, with a 66 percent career success rate and five steals in nine tries in 2019.  (Callas - mlb.com - 8/4/19)

2017: A broken right hamate bone impacted part of the season.

May 18-28, 2018: Diaz was on the DL.

Sept 15-31, 2020: Diaz was on the 60-day IL with left groin strain.

May 23-25, 2021: Diaz was on the IL

March 30-May 19, 2023: Isan began the season on the IL

May 25-June 13, 2023: Diaz was on the IL