The Rockaway Wave
Originally Published July 25, 2025
Walks are killer for pitchers. Not only do they do the obvious of letting a runner on base without getting a hit, but they drive up pitch counts, extend innings, and oftentimes knock pitchers out of the game earlier than they otherwise would have.
Brooklyn Cyclones right-hander Joel Díaz has been one of the best pitchers in minor league baseball at not surrendering walks.
“He’s been outstanding at limiting the free passes,” Cyclones pitching coach Jordan Kraus said. “Obviously those are what come back to hurt you more times than not, so his ability to keep guys off base, and when he does get guys on base, he’s able to induce weak contact, get ground balls, and just be on top of hitters relentlessly.”
Díaz’s 4.6% walk rate is the seventh-best in High-A among pitchers with at least 50 innings pitched, fourth-best in the South Atlantic League, and the best on the Cyclones. He’s also done it with a better strikeout rate than five of the six players ahead of him in High-A, including all three of the pitchers in his league.
His walk rate is the third best in the entire Mets minor league system among those with at least 50 innings pitched, only behind former Cyclones Joander Suarez and Zach Thornton. It’s a huge improvement from last year when he had a walk rate of 8.5%, which isn’t bad, but nothing close to where it is today.
“One of [my] biggest focuses this offseason was working on the strike zone and attacking the zone, because [my] previous two years, [I] saw [I] walked too many people,” Díaz said through catcher Chris Suero, who was acting as an interpreter. “[I’m] not that type of pitcher, it’s not in [my] arsenal.”
Díaz, who joined the organization in 2021 and burst onto the scene, recording a 0.54 ERA in 50 and 1⁄3 innings in the Dominican Summer League. Brooklyn’s media guide states that he was the only qualified pitcher in all of minor league baseball to record a sub-1 ERA in 2021.
He reached Single-A St. Lucie in 2022 at just 18 years old and was the No. 10-ranked prospect in the Mets system on MLB Pipeline and No. 9 on Baseball America going into the year. He helped the St. Lucie Mets win the Florida State League championship with six shutout innings and 11 strikeouts out of the bullpen in the semifinals.
“He actually had one of the best performances I’ve ever seen,” Cyclones manager Gilbert Gómez, who was St. Lucie’s bench coach that season, said.
He was then the No. 12-ranked prospect on MLB Pipeline and No. 14 on Baseball America going into 2023, but tore his UCL in the buildup to the season.
“It was very, very hard,” Díaz said. “[I] tried to just focus on being able to come back stronger and never going back. … [I] feel like ever since that injury and from there on out, [I’ve] been a completely different person. In reality, it worked out better and good because [I] learned a lot from it.”
Díaz missed all of 2023, and after a short stint on the injured list to open up 2024, returned to the mound in May for the Florida Complex League Mets. He threw two shutout innings, allowing two hits and no walks, while striking out a pair.
“Leading up to that day, [I] was very, very anxious,” Díaz said. “[I] was also very happy, and every day that went by, the closer it got to that day of [me] throwing, [I] kept getting happier and happier. [I] couldn’t wait for that first pitch. Once [I] threw that first pitch, it was an indescribable feeling, knowing that [I] didn’t feel no pain, nothing hurt, [my] arm was good, and everything went smoothly. [I] was able to just thank God, because all the hard work that [I] put in leading up to that moment, it all paid off.”
Before 2024, Díaz was primarily a three-pitch pitcher — fastball, curveball, changeup. He said he felt hitters were starting to adjust to that mix and he wasn’t being as competitive, so he spoke to Kraus, who was St. Lucie’s pitching coach in 2024, about expanding his arsenal.
They added a two-seam fastball/sinker (the names are interchangeable) and a sweeper. The goal, Kraus said, is to give him more options to get both lefties and righties out, as well as pairing his ability to throw strikes and get weak contact with a better chance to get swings and misses.
The two-seam will help induce more weak ground balls, especially when running it in on the barrel to right-hand hitters. The way the game is trending, Kraus said, most guys have more than one fastball option to go to.
Díaz said he feels very comfortable with the two-seam, and Kraus said he’s now throwing it more than he throws his four-seam fastball.
The sweeper is the big swing-and-miss pitch. It grades out better stuff-wise, Kraus said, than the curveball, but is still very much a work in progress.
“It’s a more difficult pitch for him to throw … but it’s actually over the last month performed better than it has since we started the process way back when,” Kraus said.
The process started from scratch last season. Díaz had to learn how to shape the pitch and feel when it’s right or wrong. Then, once that’s down, he has to learn when the right situations are to use it.
“Anytime you add two pitches to somebody’s arsenal, it can be a little bit cluttered in terms of usage,” Kraus said. “So just trying to figure out how we can use those options, and use the big picture to create outs, create miss, create weak contact, [use] the game situation to understand what the right pitch call is — all those variables come into play. He’s a real cerebral guy, he’s done a really good job of buying into the process and just working on all those things.”
Díaz is less comfortable with the sweeper than he is the two-seam, but said he believes eventually it will end up as his best pitch.
“When he’s had those stretches when he’s feeling really good with it and executing with it, he’s able to create swing-and-miss with it,” Krais said. “That’s slowly been building his confidence in it, and I think it really can be a good weapon for him too. I agree with him.”
The curveball, which was his primary breaking pitch before his injury, has been eliminated.
His changeup is still a part of his arsenal, and Kraus said it’s a great pitch for him against left- hand hitters. His command of it can sometimes be touch-and-go, but when on, it’s a quality swing-and-miss pitch.
He also has a cutter/slider, which is a pitch Kraus said Díaz is very comfortable with. He can throw it in the zone for strikes or out of the zone to try to get hitters to chase whenever he wants, and it’s his second most-used pitch behind his heater.
“He calls it a cutter; it kind of turns into a little bit of a slider/cutter hybrid at times,” Krais said. “I think that’s the next step for him with that pitch, is being able to shape it a little bit both ways.”
In 2025, Díaz does not appear on either MLB Pipeline or Baseball America’s Mets’ top 30 prospects list. It’s a product of missing all of 2023, not pitching particularly well in Single-A in 2024, and the Mets’ farm system drastically improving around him. However, despite the general public’s eyes elsewhere, he’s in the midst of easily his best season since 2021.
In 67 and 2⁄3 innings, Díaz has posted a 3.59 ERA and 1.17 WHIP with 73 strikeouts and just 13 walks. He’s started 10 of the 17 games he’s appeared in, and is used in a piggyback, multi-inning relief role when he doesn’t start.
“He just throws strikes,” Gómez said. “He fills up the strike zone … he attacks the zone consistently, swing-and-miss has been there all year. Especially coming back from basically missing a year, and he’s been able to take the ball every five days and compete, that’s huge for us. He’s a guy, he just likes to be out there and compete, and that’s something we really like about him.”
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