Kelley struggled with his fastball this season as batters hit .362 against it with a wOBA of .449 due to the 11 extra base hits allowed in 96 at-bats. He could not seem to get guys to whiff as often as he did in the past couples seasons as his whiff rate with it dropped under 20% (13%) for the first time since 2014.
For the first time since 2015, Kelley’s most utilized pitch was his slider, which is not surprising since he’s been able to contain batters to an average of .220 or worse every season since. He was able to generate a whopping 71% strike rate which is a direct result of guys often chasing the pitch outside of the zone (O-Swing of 45%) and eventually ended the season with a tremendous 39 strikeouts in 126 plate appearances.
Kelley’s fastball sat at 91.1 mph similar to 2017 (91.9). However, the results were drastically different as it allowed just a .220 batting average this year compared to 2017’s mark of .323.
At 81 mph Kelley has good velocity differential off his fastball (91.1 mph). Overall the pitch was very effective limiting batters to a paltry .197 wOBA, 36.9% chase rate and was good for a 5.4 pVal.