D-backs Reportedly Parting With Pitching Coach in Surprise Decision

A surprising choice after 2026's pitching results.

May 8, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitching coach Brian Kaplan against the New York Mets at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | IMAGN IMAGES via Reuters Connect

The Arizona Diamondbacks are making a surprising decision regarding their coaching staff.

According to a new report from MLB.com's Steve Gilbert, the Diamondbacks will not be bringing back pitching coach Brian Kaplan for 2027 and beyond.

Kaplan spent the 2024 and 2025 seasons in Arizona with mixed pitching results, but will not get a third year in Arizona.

Diamondbacks to part with pitching coach Brian Kaplan

Jul 21, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitching coach Brian Kaplan against the Athletics at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | IMAGN IMAGES via Reuters Connect

Kaplan's contract ran through 2026. The move was not a firing, but a choice to not re-sign him to a new contract. The Diamondbacks hired him away from the Philadelphia Phillies, where he served as assistant pitching coach and director of pitching development.

Kaplan's hiring served to replace Arizona's incumbent veteran pitching coach Brent Strom following the 2023 season, in which the Diamondbacks' pitching staff struggled outside of a few contributors.

When Kaplan took over, the results were a bit rough at first. Arizona's 4.62 team ERA in 2024 was the 27th-ranked number in baseball, accompanied by a 27th-ranked 4.79 rotation ERA and 4.41 bullpen ERA, which sat at 25th in the majors. That was a step back from 2023 under Strom.

The Diamondbacks' team ERA improved to 4.49 in 2025, though their bullpen plummeted even further to 4.82.

Granted, some of those results could have been attributed to the talent afforded Kaplan and the Diamondbacks. Many a quality arm went down with injury, and Arizona had to turn to quite a few unproven rookies and joruneymen arms in the process.

The Diamondbacks' 2026 season was a departure from those trends. In fact, it seemed as if Kaplan and the pitching staff had improved to a significant degree. Arizona held an 18th-best 4.18 team ERA, 16th-best 4.07 bullpen ERA and 19th-ranked rotation ERA.

Granted, the Diamondbacks are not exactly among the top pitching teams in baseball. But it did seem as if Kaplan was able to work with what he was given more effectively in 2026. It's also worth noting that Arizona has struggled in recent years with developing home-grown pitching talent.

As of this writing, it is unknown who may or may not be a candidate to replace Kaplan. Arizona made the decision to retain manager Torey Lovullo on a two-year extension early in the offseason, but that did not necessarily guarantee a wholesale return of Arizona's coaching staff.

There may be more changes to that staff on the horizon, as well.