Although they have not thrown an MLB pitch in 2023, Zac Gallen threw 7,715 pitches that were tracked by the PITCHf/x system between 2019 and 2022, including pitches thrown in the MLB Regular Season and Spring Training. In 2022, they relied primarily on their Fourseam Fastball (94mph) and Curve (81mph), also mixing in a Change (86mph) and Cutter (90mph). He also rarely threw a Slider (88mph) and Sinker (95mph).
In 2022, compared to other RHP:
His fourseam fastball has less armside movement than typical and has essentially average velo. His curve has a sharp downward bite, is slightly harder than usual, has primarily 12-6 movement and results in somewhat more groundballs compared to other pitchers' curves. His change is slightly firmer than usual and has some natural sink to it. His cutter has extreme cut action, generates fewer whiffs/swing compared to other pitchers' cutters, results in somewhat more groundballs compared to other pitchers' cutters, has slightly above average velo and has some natural sink. His slider is thrown extremely hard and has short glove-side cut. His sinker (take this with a grain of salt because he's only thrown 1 of them in 2022) is basically never swung at and missed compared to other pitchers' sinkers, is an extreme flyball pitch compared to other pitchers' sinkers, has well above average velo and has little sinking action compared to a true sinker.