2026 Fantasy Baseball Value Ace: George Kirby

Kirby has yet to reach elite SP1 status, but he brings plus command and an elite fastball. With an uptick in a secondary swing and miss pitch, he would develop into a difference-maker front-end starter.

SP George Kirby, Seattle Mariners | Arianna Grainey-Imagn Images

Kirby is another 2025 pitching casualty for the Mariners. A right shoulder injury in early March pushed him to the sidelines until May 22nd. Batters drilled him over his first two starts (11 runs, 16 baserunners, and eight strikeouts over 8.2 innings).

George Kirby, Seattle Mariners (NFBC ADP – 61)

2026 George Kirby Pitching Stats | Shawn Childs

Over his next 13 games, he went 8-3 with a 2.83 ERA, 0.983 WHIP, and 82 strikeouts over 76.1 innings. Kirby allowed three runs or fewer in six of his last eight games, but two of those outcomes killed fantasy teams (14 runs, 25 baserunners, and five strikeouts over 6.2 innings). Other than his four poor games, he went 10-5 with a 2.77 ERA, 0.985 WHIP, and 124 strikeouts over 110.2 innings.

Much of his failure came on the road (5.16 ERA, 1.281 WHIP, and 64 strikeouts over 59.1 innings). His exit velocity (90.6) and hard-hit rate (43.9%) against him were the highest of his career. Batters squared up more balls (line drive rate – 22.3%), but Kirby lowered his flyball rate (33.5% - 40.7% in 2024).

George Kirby's 3Ks in the 1st.

All on 99mph ⛽️ pic.twitter.com/LT7epR8S3h

— Rob Friedman (@PitchingNinja) October 5, 2025

His average fastball (96.2 mph) matched his last two seasons. Kirby faded his split-finger fastball (3.2% usage – 10.2% in 2024). Batters struggled to hit his four-seamer (.196 BAA), but the rest of his arsenal (sinker – .328 BAA, slider – .257 BAA, and curveball – .258 BAA) wasn’t worthy of ace status. In 2024, Kirby threw his slider (.218 BAA) with success.

Fantasy Outlook: The drawing card to Kirby is command, and his strikeout rate (9.8) was the best of his career last year. He still lacks that winning swing-and-miss off-speed pitch, required to push him to ace status. Maybe the shoulder issue was caused by his split-finger pitch. I’d like to hear that Kirby is working on some form of a changeup in 2026. His pluses are his fastball velocity, command, and slider, but is it enough to fight for in fantasy drafts? Solid SP2, with help in ERA, WHIP, and strikeouts.