New York Mets
Although they have not thrown an MLB pitch in 2024, R.J. Alvarez threw 598 pitches that were tracked by the PITCHf/x system between 2013 and 2022, including pitches thrown in the MLB Regular Season and Spring Training. In 2022, they relied primarily on their Slider (83mph) and Sinker (93mph), also mixing in a Fourseam Fastball (93mph) and Change (87mph).
In 2022, compared to other RHP:
Their slider (take this with a grain of salt because they've only thrown 18 of them in 2022) has exceptional depth, results in more flyballs compared to other pitchers' sliders and has short glove-side cut. Their sinker (take this with a grain of salt because they've only thrown 17 of them in 2022) generates an extremely high number of swings & misses compared to other pitchers' sinkers, has heavy sinking action and is an extreme flyball pitch compared to other pitchers' sinkers. Their fourseam fastball (take this with a grain of salt because they've only thrown 9 of them in 2022) is basically never swung at and missed compared to other pitchers' fourseamers, is an extreme flyball pitch compared to other pitchers' fourseamers, has some natural sinking action and has essentially average velo. Their change (take this with a grain of salt because they've only thrown 7 of them in 2022) generates an extremely high number of swings & misses compared to other pitchers' changeups, has surprising cut action, dives down out of the zone, results in more flyballs compared to other pitchers' changeups and is slightly firmer than usual.