Tillman’s four-seamer was terrible the last two years (-11.0 pVal in 2017, -6.5 pVal in 2018), which, as his primary offering, does not bode well. Losing 1.7 mph in average velocity to drop below 90 mph, his fastball gave up .400 BAA (38.7 LD%), .400 ISO and a 239 wRC+.
While Tillman’s slider (-2.4 pVal) nearly doubled its swinging-strike rate (6.1% in 2017 to 11.1%) and greatly improved its O-swing% (29.3% in ’17 to 44.3% in ’18) and K rate (16.7%, up from 11.1% in ’17), it was hampered by a .355 BAA, 130 wRC+ and an 8.3-point jump in BB%.
Having lost a full tick in average velocity, Tillman’s changeup still managed to register a positive pVal (0.2) in 2018. But a lot of that is fool’s gold, and the velocity was just the beginning. First, the pitch’s swinging-strike rate dropped in half from 10.5% in 2017 to 4.8% in 2018, and it put up a 0.0 K-BB%. While the pitch was rarely hit hard (.091 ISO, 0.0 HR/FB%), it did give up a .328 BAA and 118 wRC+.
For the second year in a row, Tillman’s sinker was a stinker (-6.5 pVal). In 80 pitches it gave up a 38.9 FB% and a 57.2 HR/FB% without generating a single whiff. As a whole, it gave up a .474 BAA with a .737 ISO and a 364 wRC+ in 2018.
Tillman’s curveball gave up a crazy-high 42.0 line-drive rate, so it seems fortunate that it was only hit for a .286 average and a 77 wRC+ in 2018. At that line-drive rate, a larger sample than 60 pitches would have shown much worse results.