Although he has not thrown an MLB pitch in 2018, Jon Lester threw 35,926 pitches that were tracked by the PITCHf/x system between 2007 and 2017, including pitches thrown in the MLB Regular Season, the MLB Postseason and Spring Training. In 2017, he relied primarily on his Fourseam Fastball (92mph) and Cutter (88mph), also mixing in a Curve (76mph), Sinker (91mph) and Change (85mph).
Basic description of 2017 pitches compared to other LHP:
His fourseam fastball has essentially average velo. His cutter has slightly above average velo. His curve generates an extremely high number of swings & misses compared to other pitchers' curves, has little depth and results in somewhat more flyballs compared to other pitchers' curves. His sinker is a real worm killer that generates an extreme number of groundballs compared to other pitchers' sinkers, generates more whiffs/swing compared to other pitchers' sinkers and has some natural sinking action. His change is much firmer than usual, results in somewhat more groundballs compared to other pitchers' changeups, has slight armside fade and has some natural sink to it.