Although they have not thrown an MLB pitch in 2023, Sam Selman threw 1,944 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 (90mph) and Slider (79mph). He also rarely threw a Sinker (90mph).
In 2022, compared to other LHP:
His fourseam fastball has heavy sinking action, is straight as an arrow, generates a high number of swings & misses compared to other pitchers' fourseamers and has slightly below average velo. His slider sweeps across the zone, has below average velo and results in somewhat more flyballs compared to other pitchers' sliders. His sinker (take this with a grain of salt because he's only thrown 16 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 and has surprisingly little armside run.