Although he has not thrown an MLB pitch in 2019, Jake Arrieta threw 22,374 pitches that were tracked by the PITCHf/x system between 2008 and 2018, including pitches thrown in the MLB Regular Season, the MLB Postseason and Spring Training. In 2018, he relied primarily on his Sinker (94mph) and Slider (90mph), also mixing in a Change (89mph) and Curve (81mph). He also rarely threw a Fourseam Fastball (93mph).
Basic description of 2018 pitches compared to other RHP:
His sinker has slight armside run and has slightly above average velo. His slider is thrown extremely hard, has less than expected depth and results in somewhat more groundballs compared to other pitchers' sliders. His change is thrown extremely hard, generates fewer whiffs/swing compared to other pitchers' changeups, results in somewhat more groundballs compared to other pitchers' changeups, has slight armside fade and has some natural sink to it. His curve has a sharp downward bite, is slightly harder than usual and has slight glove-side movement. His fourseam fastball has essentially average velo.