Boston Red Sox
Although they have not thrown an MLB pitch in 2024, Héctor Rondón threw 7,688 pitches that were tracked by the PITCHf/x system between 2010 and 2021, including pitches thrown in the MLB Regular Season, the MLB Postseason and Spring Training. In 2021, they relied primarily on their Fourseam Fastball (94mph) and Slider (84mph), also mixing in a Sinker (94mph). He also rarely threw a Change (88mph).
In 2021, compared to other RHP:
Their fourseam fastball has some natural sinking action, has essentially average velo and results in somewhat more flyballs compared to other pitchers' fourseamers. Their slider generates an extremely high number of swings & misses compared to other pitchers' sliders, has exceptional depth and is an extreme flyball pitch compared to other pitchers' sliders. Their sinker (take this with a grain of salt because they've only thrown 19 of them in 2021) generates an extremely high number of swings & misses compared to other pitchers' sinkers, has slight armside run and has slightly above average velo. Their change (take this with a grain of salt because they've only thrown 5 of them in 2021) has an obvious armside fade, generates more whiffs/swing compared to other pitchers' changeups, is much firmer than usual, results in more flyballs compared to other pitchers' changeups and has some natural sink to it.