Cincinnati Reds
Although they have not thrown an MLB pitch in 2024, Ryan Mattheus threw 3,223 pitches that were tracked by the PITCHf/x system between 2008 and 2016, including pitches thrown in the MLB Regular Season and Spring Training. In 2016, they relied primarily on their Sinker (92mph) and Fourseam Fastball (92mph), also mixing in a Splitter (86mph). He also rarely threw a Slider (82mph).
In 2016, compared to other RHP:
Their sinker (take this with a grain of salt because they've only thrown 18 of them in 2016) is an extreme flyball pitch compared to other pitchers' sinkers and has little sinking action compared to a true sinker. Their fourseam fastball (take this with a grain of salt because they've only thrown 8 of them in 2016) generates an extremely high number of swings & misses compared to other pitchers' fourseamers, is an extreme flyball pitch compared to other pitchers' fourseamers, has essentially average velo, has slight armside run and has some added backspin. Their splitter (take this with a grain of salt because they've only thrown 3 of them in 2016) is basically never swung at and missed compared to other pitchers' splitters, has surprising cut action and is an extreme flyball pitch compared to other pitchers' splitters. Their slider (take this with a grain of salt because they've only thrown 1 of them in 2016) is basically never swung at and missed compared to other pitchers' sliders, is an extreme flyball pitch compared to other pitchers' sliders, has much less depth than expected and has primarily 12-6 movement.