Report: Brian Kaplan will not return as Diamondbacks’ pitching coach
During Kaplan's tenure, the Diamondbacks pitched to a 4.34 ERA in 2,886 innings — 22nd in MLB during that span.
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The Arizona Diamondbacks have parted ways with pitching coach Brian Kaplan, according to MLB.com’s Steve Gilbert.
Kaplan joined the D-backs ahead of the 2025 season after serving three seasons as the assistant pitching coach for the Philadelphia Phillies. His contract expired after this season, and Arizona opted not to bring him back.
During Kaplan’s tenure, the Diamondbacks pitched to a 4.34 ERA in 2,886 innings — 22nd in MLB during that span, according to FanGraphs.
Arizona’s pitching under Kaplan had its ups and downs: Franchise mainstays Merrill Kelly and Zac Gallen showed significant decline, while Eduardo Rodriguez had a resurgent 2026 season after a rough start to his stint with the D-backs.
Improvement from the pitching staff was most visibly seen in the bullpen, where Arizona’s relievers were among the worst in 2025 (29th in win probability added), but among the best in 2026 (fourth in win probability added).
Kaplan’s departure comes as the first major decision regarding Torey Lovullo’s staff since the manager signed a two-year extension last Thursday. Lovullo hinted that his coaching staff may not look the same next season when speaking to reporters at a press conference after signing his extension.
“I’m going to have some conversations, and I need to think through some things very clearly,” Lovullo said. “To be honest with you, I haven’t thought about it at all, and I want to be fair to that group. I told them on the last day in San Diego that I didn’t know what was happening with me, and once I figured that out, I will start to move downfield with the next group of decisions.”
Whoever the incoming pitching coach is will become the club’s fifth since Lovullo was hired prior to the 2017 season.
With key pitchers like Michael Soroka, Kevin Ginkel, Taylor Clarke and Gallen due to hit free agency, it’s possible that the sudden pitching coach change could have an immediate impact on what the future staff looks like.
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Comments
15 Comments
I can understand your comments but let me ask you these two questions:
Question: Pfaadt pitched poorly (ERA over 5.0) for the 2025 season and the start of the 2026 season. Pfaadt was sent to Reno where the pitching staff made two changes to his delivery and he went from a terrible pitcher to an elite pitcher. Why didn't Kaplan made these changes when Pfaadt was with the Dbacks?
Question: Did Kaplan pushed for Gallen and Kelly? If he did, he should be held accountable for wanting these two has-beens.
Doesn't matter to me who the "pitching" coach is. The problem with pitching is the composition of the staff, not the pitching coach. As far as I can tell, Kaplan had negligible effect of the production of the pitching staff. You can't attribute the moderate success of the bullpen or the overall failure of the starting rotation to the coach. That's the responsibility of the front office.
Perhaps this is a smokescreen to shift blame without addressing the real problems of this club.
The DBacks blame game roulette wheel never lands on Lovullo.