Seattle Mariners pitcher George Kirby walks to the bullpen before a game against the Boston Red Sox on July 31, 2024, at Fenway Park. David Butler II-Imagn Images

ANALYSIS: Despite His Numbers, George Kirby Looks Ready For Activation

Originally posted on Seattle Mariners on SI
By Teren Kowatsch | Last updated May 17, 2025 4:30 PM ET

The Seattle Mariners have been hit with injuries through the first 43 games of the season. The starting rotation has seen three pitchers land on the injured list: George Kirby, Logan Gilbert and Bryce Miller. The Mariners could end up catching a break on that front with one starter nearing his return.

Kirby, a 2023 All-Star, made his third rehab start for the Triple-A Tacoma Rainiers on Friday. It was the worst outing of his rehab assignment from a numbers standpoint. He pitched four innings, struck out four and allowed four earned runs on 10 hits (two home runs).

Kirby a 7.20 ERA this season with 13 strikeouts in 10 innings pitched across three starts on his assignment. He's allowed eight earned runs on 15 hits (three home runs).

George Kirby got the full PCL experience in his 3rd rehab start. Final line: 4IP, 10H, 4R, 0BB, 4K, 64-48. pic.twitter.com/KLJHWSfN5u
— Mariners Minors (@MiLBMariners) May 17, 2025

When Kirby got assigned to Tacoma, the expectation was he would make two-to-three rehab starts before being activated off the injured list. He's been out since March 7 due to right shoulder inflammation and began the year on the 15-day IL.

Kirby's numbers aren't encouraging when discussing his potential return to the major league staff, but it's the physical benchmarks that are the most important, and it looked like he cleared those Saturday.

Kirby threw 64 pitches, including 48 strikes. He threw 54 pitches in his second rehab outing and 42 in his first. The majority of the damage done against Kirby on Saturday happened in the first two innings, which is a good sign that his increased usage didn't labor him.

Kirby also gained his velocity back. His fastball maxed out at 97.5 mph. His average fastball velocity was at 96 mph in 2024, according to Baseball Savant.

Kirby's fastball is back, and the higher pitch count didn't noticeably affect him. Those, and how Kirby feels after his rehab starts, are the major things needed to nail down before he's activated off the IL.

Seattle general manager Justin Hollander said that the team would take it start-by-start with Kirby in Tacoma and see how he feels. There's no guarantee his next start will be in the major leagues. But unless the Mariners choose to be extra cautious, it seems like he's ready.

If Kirby's next outing is in the major leagues, it will likely be on May 22 in the first of a four-game series between Seattle and the Houston Astros.

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

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