Hahn barely threw his changeup during the brief time he was in the majors, only using it 4.7% of the time compared to a 9.1% usage rate over his career. It was also a fair bit faster in 2019, clocking in at an average of 87.2 mph compared to a career average of 84.7 mph, marking a similar increase when compared to his fastball.
Hahn spent most of the 2019 season rehabbing from a UCL injury that kept him off the mound for all of 2018, so he’s coming into the 2020 season with a lot of questions. The strikeout potential is there with a 13.50 K/9 rate in his six games in the majors, but control is a big question, with a 11.57 BB/9 rate over the same time. He threw his fastball harder in his return than he had in the past (95.1 mph compared to a 92.6 mph career average), so hopefully he can put up more consistent numbers now that he’s healthy.
Hahn had never used his slider more than 9.9% of the time in the past, and never threw it in 2016 according to available data. He threw it 32.71% of the time in his six games pitching for the Royals last season, so it will be interesting to see if he continues to use this pitch as his primary offspeed offering.
Hahn’s fastball has been heating up, with average climbing over two miles per hour to 94.2 in 2016, with a peak of 97.5. KRate fell to just 4.1% and opponents hit a career high .344 and .925 OPS resulting in a pVAL of -2.6
Hahn’s curveball averaged 76mph in 2016 and 2017 and K rate remains high at 42.2%, with a swinging strike rate of 13.3% with an OSwing of 34.1%. Continued reduction in movement has led to hitters average climbing 60 points to .310 in 2017 and posted a pVAL of -4.7 in his most recent campaign.
Hahn’s changeup saw a reduction in swinging strikes in 2017, down to a rate of just 3.9%. As a result, opponent’s average climbed to .300, but power off the pitch was somewhat limited with to .400 slugging. Groundball rate has been on the decline, falling to 40% in 2017, with line drive% climbing.
Hahn’s slider has seen significant improvement in recent seasons, having added over 4 miles per hour. Swinging strike rate climbed to 17% in 2017, thanks primarily to his ability to make opponents chase, with an impressive OSwing of 40%. Opponents hit just .219 with a .063ISO, leading to a pVAL of 2.2