Diamondbacks left-handed reliever A.J. Puk is nearing the one-year anniversary of the internal brace procedure he underwent on his elbow on June 20, 2025. Puk is now dealing with another issue that will delay a potential 2026 return. The Diamondbacks have paused his rehab as a result of left shoulder discomfort, according to Nick Piecoro of the Arizona Republic. Puk will undergo an MRI.
The Athletics drafted Puk sixth overall in 2016. He continued as a premium starting pitching prospect in the minors over the next couple of years. Unfortunately, though, injuries have plagued Puk throughout his professional career and largely limited him to a relief role. He underwent Tommy John surgery in 2018, keeping him out all of that season. The A’s promoted Puk to the majors in August 2019, but after an encouraging late-season debut, a shoulder strain shelved him for the entire pandemic-shortened 2020 campaign. He has since gone on the IL five more times with various arm troubles, including his current 60-day placement.
When he has taken the mound, the 31-year-old Puk has held his own. During a mostly healthy stretch with the A’s, Marlins and Diamondbacks from 2022-24, he made 178 appearances and fired 180 2/3 innings of 2.94 ERA ball with a 31.1 percent strikeout rate and a walk percentage of 6.4. He was in top form after Arizona acquired him from Miami ahead of the 2024 trade deadline. Puk posted a pristine 1.32 ERA with 43 strikeouts and a mere five walks over 27 1/3 frames.
The Diamondbacks hoped for similar dominance last year, but Puk was only healthy enough to total eight innings. His most recent appearance in the majors came on April 17, 2025. While Arizona could have non-tendered Puk in the offseason, it kept him around on a $3.1MM salary for his final year of team control. Puk had been working back on a rehab assignment before this shoulder problem cropped up in a 24-pitch outing with Triple-A Reno on June 5.
The Diamondbacks have started the year 35-34, putting them 8 1/2 back of the NL West-leading Dodgers. That may be too big of a deficit to overcome, but they are just a half-game out of a wild-card spot. A bullpen that has gotten nothing from Puk or June 2025 Tommy John recipient Justin Martinez ranks 20th in ERA (4.27) and 25th in K-BB percentage (10.5). However, a good portion of the damage has come against current minor leaguers Brandon Pfaadt (5.91 ERA in 21 1/3 relief innings) and Andrew Hoffmann (7.71 ERA in 11 1/3 frames).
The Diamondbacks have gotten impressive results from a unit consisting of closer Paul Sewald, Kevin Ginkel, Taylor Clarke, Juan Morillo, Ryan Thompson, Jonathan Loáisiga and Brandyn Garcia. They have each logged ERAs ranging from 2.12 to 3.20, and all of them carry decent or better peripherals. There isn’t much variety with Puk unavailable, though, as Garcia is the lone southpaw in the group. Martinez, another righty, could return sometime in the second half, per the team’s injury report at MLB.com. He threw his eighth bullpen session on Friday.
Expecting to buy before the Aug. 3 trade deadline, D-backs general manager Mike Hazen has already identified the bullpen as an area he would like to address. If Puk’s latest injury proves severe, it could increase Hazen’s urgency to upgrade his relief corps this summer.
