An Honest Assessment of Diamondbacks 2025 Bullpen Construction

An all too familiar scene took place at Chase Field last night. The Arizona Diamondbacks had battled to take a lead in a hard fought ballgame against the Los Angeles. But once again their hopes of victory evaporated into thin air after yet another bullpen meltdown.

This time they had come back from an 8-3 deficit to take an 11-8 lead into the top of the ninth, but Kevin Ginkel and Ryan Thompson combined to give up six runs in a 14-11 loss.

This was somewhat of a repeat of what took place April 18 in Chicago. The Diamondbacks stormed back from a 7-1 deficit against the Cubs to score 10 runs in the eighth inning. Then their bullpen, working without either A.J. Puk or Justin Martinez, imploded to allow six runs in the bottom of the inning, ultimately losing 13-11. Struggling Joe Mantiply and Bryce Jarvis were optioned to Reno the next day.

It's not like the bullpen had been doing well in between those two disasters. From April 19-May 8 the relief core had pitched to a 4.69 ERA and an even worse 5.32 FIP. So they can't blame bad luck.

During the offseason General Manager Mike Hazen repeatedly stated he wanted to add to the bullpen, preferably a back-end, high-leverage reliever. But various attempts to sign or trade for one fell through, and the team's allocation of resources ultimately went into signing starter Corbin Burnes to a six-year, $210 million dollar contract.

That's not to say they didn't add. Hazen signed Kendall Graveman, who between 2021-2023 posted a 2.74 ERA for the Mariners, White Sox, and Astros over 187 innings pitched. He also recorded 24 saves. Graveman also came with an injury history, and had missed all of 2024 due to shoulder surgery. Hence his availability on a one-year, $5 million dollar deal with an option.

Unfortunately Graveman came down with an injury early in camp, a lower back strain, that set him back until now. He just completed two rehab assignment games with the Reno Aces and is projected to join the club either Sunday or Monday.

Another addition was Shelby Miller, who was signed to a minor league contract. Miller impressed in spring, and made the Opening Day roster, and has been one of the best pitchers on the team so far this year. He's pitched in 16 games, thrown 16.2 innings and posted a minuscule 1.08 ERA (3 runs allowed, two earned). The intention was never for Miller to be the closer however.

Another addition came at the very end of Spring Training. Left-hander Jalen Beeks was released by the Pirates. The D-backs swooped in on March 26, one day before Opening Day, signing him to a one-year deal worth $1.25 million dollars. He's been the workhorse of the pen, throwing 21.2 innings while posting a 2.08 ERA.

Thus the Diamondbacks entered the 2025 season with A.J. Puk and Justin Martinez as their co-closers, and it seemed to be working the first three weeks of the season. Through April 17 they had combined for six saves and five holds. Neither had blown a lead.

Unfortunately Puk got hurt, and is on the IL with a flexor tendon strain. Now on the 60-day IL, he's just began a throwing program and is not eligible to return before June 18. Martinez went through a dead arm phase, pitched ineffectively with a severe velocity loss, and ended up on the 15-day IL himself.

While all this was going on, Kevin Ginkel was injured in Spring Training too. He returned from a sore shoulder on April 30. He'd already been somewhat shaky, allowing runs in three of his first five outings on five hits, three walks, and two homers.

Then Friday night's meltdown happened. Working for the third time in four days his velocity was down and there was no sharpness to his breaking pitches. Four batters in he had surrendered four straight hits and three runs.

Ryan Thompson meanwhile has been a shadow of the pitcher he was for his first season and a half with Arizona. The formerly reliable sidewinder had only allowed three homers in 91 innings pitched dating back to August 27, 2023 (including Postseason). This year he has allowed three homers in 15.2 innings, including Ohtani's game winning three-run blast on Friday. Thompson has a 5.74 ERA and 5.02 FIP.

One shutters to think how bad things would be had the Diamondbacks not picked up Miller and Beeks. Even with those strong additions, the depth is simply not there to withstand the injuries to Puk, Martinez, Ginkel, and Graveman.

One area to look at is the reluctance to spend money on the back-end of the bullpen. There were a number of high-leverage relievers available on the free agent market, but it became apparent the D-backs were not able to compete for any of these pitchers. Below is a chart showing the potential high-leverage reliever targets, their age and what they signed for, and their performance to date.