Seattle Mariners
Although they have not thrown an MLB pitch in 2024, Jonathon Niese threw 18,891 pitches that were tracked by the PITCHf/x system between 2008 and 2016, including pitches thrown in the MLB Regular Season and the MLB Postseason. In 2016, they relied primarily on their Sinker (89mph), Fourseam Fastball (90mph) and Cutter (87mph), also mixing in a Change (83mph) and Curve (75mph).
In 2016, compared to other LHP:
Their sinker has some natural sinking action. Their fourseam fastball has heavy sinking action, results in many more groundballs compared to other pitchers' fourseamers, has essentially average velo and has slightly less natural movement than typical. Their cutter has some natural sink and has strong cutting action. Their change is a real worm killer that generates an extreme number of groundballs compared to other pitchers' changeups, dives down out of the zone, generates fewer whiffs/swing compared to other pitchers' changeups and has slight cut action. Their curve has a sharp downward bite, results in somewhat more flyballs compared to other pitchers' curves and has slightly below average velo.