Seattle Mariners pitcher George Kirby throws during a game against the Oakland Athletics on Sept. 4 at Oakland Coliseum. Eakin Howard-Imagn Images

Seattle Mariners Starting Pitcher George Kirby Takes Major Step in Recovery

Originally posted on Seattle Mariners on SI
By Teren Kowatsch | Last updated Apr 25, 2025 7:45 PM ET

SEATTLE — The Seattle Mariners starting rotation hasn't been at full strength for almost three months.

Starting pitcher and 2023 All-Star George Kirby was shut down March 7 during spring training due to right shoulder inflammation. The initial tentative timeline had Kirby returning in late April, but a return in mid-to-late May or early June more likely at this point.

Kirby has been hitting all the benchmarks in his recovery and took the latest step in his rehabilitation before the Mariners game against the Miami Marlins on Friday.

Kirby was at T-Mobile Park and threw a bullpen several hours before first pitch.

George Kirby throwing a bullpen.#Mariners #TridentsUp pic.twitter.com/LQjvpoDkCO
— Teren Kowatsch (@Teren_Kowatsch) April 25, 2025

Seattle general manager Justin Hollander spoke with the media before the game against Miami and detailed the next steps in Kirby's progression. If the bullpen went well with no setbacks, Kirby will throw a live bullpen next. Hollander said that also could happen in the Mariners current homestead, but wasn't certain on that.

"I don't know when (the live bullpen) will be," Hollander said Friday. "Some of that depends on how today goes and how he feels afterwards. But he is here ... but the next step is that he will throw a live BP here, hopefully on this homestand."

Kirby is regarded as one of the best command pitchers in the league. He had a 3.53 ERA in 33 starts with 179 strikeouts in 191 innings pitched last season. The Mariners have used Emerson Hancock and Luis F. Castillo in five combined starts in place of Kirby.

If Kirby does check off a live bullpen in Seattle's current homestead, the next step would be a rehab assignment, likely with the Triple-A Tacoma Rainiers or High-A Everett AquaSox.

This article first appeared on Seattle Mariners on SI and was syndicated with permission.

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