Although he has not thrown an MLB pitch in 2018, Keith Hessler threw 754 pitches that were tracked by the PITCHf/x system between 2015 and 2017, including pitches thrown in the MLB Regular Season and Spring Training. In 2017, he relied primarily on his Fourseam Fastball (92mph) and Slider (84mph).
Basic description of 2017 pitches compared to other LHP:
His fourseam fastball generates a very high amount of groundballs compared to other pitchers' fourseamers, has good "rising" action, has essentially average velo and has slightly less natural movement than typical. His slider is a real worm killer that generates an extreme number of groundballs compared to other pitchers' sliders and has less than expected depth.