Following rollercoaster first half, A.J. Puk feeling 'really confident'

Entering the 2024 regular season, it’s reasonable to say nobody on the Miami Marlins had more momentum and hype than left-handed pitcher A.J. Puk.

Puk dazzled in spring training, where he was called upon to start games for the first time since 2019 due to injuries in Miami’s rotation. The former first-round pick and top prospect started four games (13.2 IP) and allowed just two earned runs, pitching to the tune of a 1.31 ERA with a BB/K ratio of 4/23. After his stellar showing in the spring, Puk earned the number two spot in the rotation and had Fish fans and the front office alike buzzing. What ensured, however, was very on-brand for the 2024 Marlins.

Puk’s first start against the Pirates was a complete 180 from the version of him that flashed just weeks before, as he was only able to complete two innings after walking six Buccos, amounting to four earned runs. Poor location and inability to go deep into games were two themes that continued to haunt Puk in his next three outings, as the 6'7" lefty combined for eleven walks against the Angels, Yankees and Cubs, while not being able to get through five innings one time. After a seven-earned-run blowup outing in Chicago where he was only able to top 93 mph on his four-seam fastball, Puk was placed on the 15-day IL with shoulder fatigue.

In mid-May, Puk re-joined the big league club, although this time around, he was back in the bullpen. From his first outing back in the 'pen through June 17, he was still below-average, sporting a 4.61 ERA and 4.54 FIP across 11 appearances, highlighted by a three-run homer off the bat of Tyler Freeman in a 2-2 ballgame on June 9. Positively, though, Puk demonstrated much better control across all his pitches as evidenced by only three walks allowed in that span.

To rub salt in the wound of Puk's middling performance, JJ Bleday, who was sent to Oakland in exchange for Puk back in February 2023, enjoyed one of the best stretches of his young big-league career, slashing .260/.345/.488 with 16 extra-base hits in the same month-plus span.

While Puk was allowing less free passes, things still needed to change if the one-time closer wanted to get high-leverage innings like he did a season ago. The change was a simple tweak of a pitch grip.

On June 23 against the Mariners, instead of throwing his patented sweeper that saw so much success a season ago, Puk threw a harder slider with the same grip he used back in college. Ever since, Puk has been nothing short of dominant.

Entering Tuesday, Puk has not allowed an earned run since going back to his old breaking pitch. In 12 appearances, he has allowed three hits and three walks, while striking out 19.

What has changed about the slider specifically? Following his 1-2-3 outing against the meat of the White Sox order on July 6, his manager, Skip Schumaker, noted the increase in velo and "much different break."

"And then, you saw how the frontdoor two-seam at 97 to (Luis) Robert to strike him out," Schumaker added. "That's real stuff. That's not easy to hit." On the same day, when asked about the thought process to revert to the old pitch, Puk said he "went back to the harder slider, (I) kind of got away from the sweeper. I don't know if it was a little more bigger this year, or a little slower than what it was last year. So I just needed to make an adjustment and come back to the harder one."

With the up-and-down first half behind him, Puk stated before Sunday's game that he's "real confident" at this stage of the season. "I'm feeling good. I'm just looking out there, just trying to win some ballgames here and just keep helping the team." Puk also detailed that "getting comfortable back in the bullpen" was one of the reasons he was able to push through his rough start.

Now in the middle of July, Puk has cemented himself as a legitimate trade candidate as we inch closer and closer to the MLB trade deadline on July 30. With his club control carrying through the 2026 season, Puk could net a solid return of prospects for Peter Bendix and Co. or be packaged with somebody like Jazz Chisholm Jr. to entice a contender to part with true impact talent.