Diamondbacks 2025 Player Projections: A.J. Puk

Puk appears poised to dominate again in 2025 for the Diamondbacks

Arizona Diamondbacks pitcher A.J. Puk (33) delivers a pitch on July 27, 2024 at Chase Field in Phoenix. / Owen Ziliak/The Republic / USA TODAY NETWORK

This is article is part of a series reviewing the projections for each member of the Arizona Diamondbacks 40-man roster, as well as select prospects and non-roster invitees. The order of presentation was selected using a random number generator.

The projection is comprised of the average of ZiPS and Steamer rate statistic projections, which can be found at FanGraphs. The playing time projections are our own, based on our estimates. As the D-backs make further moves throughout the offseason, the playing time projections will be updated, and relevant counting stats such as home runs and WAR can be updated.

A.J. Puk, Left-Hand Reliever, Age 30

A.J. Puk 2025 Projection / Jack Sommers

Why Puk may outperform the projection

Puk's career numbers include four starts in which he gave up 14 earned runs in 13.2 innings. In his 200 career games as a reliever he has a 3.16 ERA and 3.16 FIP, almost .40 runs lower than his total career ERA.

In 2024 Puk posted a 1.72 ERA and 2.06 FIP in 57.2 IP as a reliever with the Marlins and Diamondbacks, nearly half his career average.

Puk's stuff plays way up out of the bullpen, where he throws his four-seamer 3 MPH faster on average, and his slider has an astounding 48% WHIFF rate when working in relief.

The Diamondbacks intend to use him strictly as a relief pitcher in 2025.

Why Puk may underperform the projection

Volatility in reliever ERA can be notoriously extreme. Following a trade deadline deal to the Diamondbacks on July 25 last year, Puk allowed just one earned run in his first 29 outings (0.33 ERA). He struck out 43 batters while walking just five.

But then in his final outing of the year he entered a scoreless tie in the ninth inning in a must-win game against the San Diego Padres. He allowed three runs on two homers while recording just one out. That added one full run to his D-backs ERA, ending up at 1.32.

While that is still a spectacular number, it illustrates what can happen in small sample sizes. One bad week, or a couple of bad outings back-to-back can inflate a relief pitcher's ERA and may take weeks or months to rectify.

Puk has also spent significant time on the injured list in the past. That includes shoulder (2020 and 2024), elbow (2023), and triceps (2021) injuries.

Summary

When healthy and working out of the bullpen, A.J. Puk has been a dominant pitcher. Riding his high 90's fastball and wipeout slider that ranked top 10 in WHIFF rate in MLB last year, he appears set to dominate again in 2025.

Barring injury, he is a strong bet to post at least similar run prevention numbers as the 3.28 ERA projection above, and potentially much better than that. While the team would prefer to keep him in a setup and matchup role, there is also the possibility he may end up as the closer in 2025, and have the chance to rack up double digit saves.

Related Content

Arizona Diamondbacks 2024 Player Review: A.J. Puk