Seattle Mariners
George Kirby has thrown 8,321 pitches that have been tracked by the PITCHf/x system between 2022 and 2025, including pitches thrown in the MLB Regular Season and Spring Training. In 2025, they have relied primarily on their Slider (87mph), Fourseam Fastball (96mph) and Sinker (96mph), also mixing in a Splitter (86mph). He also rarely throws a Curve (84mph) and Cutter (93mph).
In 2025, compared to other RHP:
Their slider is a real worm killer that generates an extreme number of groundballs compared to other pitchers' sliders, is basically never swung at and missed compared to other pitchers' sliders, has exceptional depth and has short glove-side cut. Their fourseam fastball generates an extremely high number of swings & misses compared to other pitchers' fourseamers, has some natural sinking action, has well above average velo and results in somewhat more groundballs compared to other pitchers' fourseamers. Their sinker generates an extremely high number of swings & misses compared to other pitchers' sinkers, is blazing fast and results in somewhat more groundballs compared to other pitchers' sinkers. Their splitter (take this with a grain of salt because they've only thrown 16 of them in 2025) is an extreme flyball pitch compared to other pitchers' splitters, has some natural sink to it and is slightly firmer than usual. Their curve (take this with a grain of salt because they've only thrown 7 of them in 2025) is thrown extremely hard, generates an extremely high number of swings & misses compared to other pitchers' curves, results in more flyballs compared to other pitchers' curves, has a sharp downward bite and has primarily 12-6 movement. Their cutter (take this with a grain of salt because they've only thrown 5 of them in 2025) generates an extremely high number of swings & misses compared to other pitchers' cutters, is blazing fast, is an extreme flyball pitch compared to other pitchers' cutters and has little cutting action.