Wilkerson’s changeup is the pitch that garners the highest of his whiffs (14%), but is also the pitch that surrenders the highest batting average against (.417) and the second highest slugging against (.750). It’s no wonder that he throws it sparingly. His change is just 7 mph slower than his fastball and matches the speed of his slider, but the pitch doesn’t get nearly the same amount of vertical movement as his slider (26 inches vs. 38 inches). When batters don’t whiff, they are making good contact.
The curveball was Wilkerson’s most effective pitch with just a .286 slugging against. It was his highest pVAL pitch at 1.0, generating an 7.02 Whiff%. The problem is that he only threw it 17.1% of the time. Averaging just 74.5 mph, Wilkerson’s curveball moved two inches more horizontally than the average curveball in the league and dropped 10 inches more than league average. The pitch only ended up in the strike zone 40% of the time, but was most effective when thrown down and below the zone. With all that drop, hitters swing over top of the pitch, getting fooled before it falls off the table.
As his primary pitch, Aaron Wilkerson threw his fastball more than half the time, but only three of the 168 fastballs were over 92 mph with the average at 89.8 mph. Like his changeup, the pitch was knocked around to the tune of a .400 batting average, .767 slugging, and a .367 ISO. Generating just an 8.93 whiff rate, the underpowered fastball unsurprisingly generated the most whiffs when thrown up in the zone and was pounded when thrown low in the zone.
Even though he threw his slider just 17.4% of the time, it was Wilkerson’s second most thrown pitch in 2019. The slider averaged 82.7 mph and was league average in both horizontal and vertical movement moving away from right-handed batters. While his fastball and changeup were hit hard, Wilkerson’s slider had a .286 BAA and a .357 SLG against. It was a pitch with a positive pVAL (0.4) surrendering an average exit velocity of just 83.6 mph.
Is there such thing as a three-true-outcomes pitch? Wilkerson’s four-seamer struck out seven batters in just nine innings last year, but it also walked three and gave up two bombs in the same span. At least there are the K’s.
The 29-year-old’s slider showed signs of effectiveness in limited appearances last year, topping 50% in O-swing and zone rates while yielding a swinging-strike rate of 10.5%. The results didn’t bear out as well on the diamond, but this pitch might have more to offer if WIlkerson gets more appearances in 2019.
Batters who swung against this curve in the strike zone made contact 100% of the time, leading to a double and a home run in five plate appearances. Ouch.
Eight batters saw Wilkerson’s changeup last year, and three made it to first base. There’s not much else to say about the pitch, but Wilkerson holds a career opponent ISO of .000 with it, so there’s that.