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When you head to Fangraphs.com and search for the league’s highest performing relievers you see Josh Hader’s name atop the list. Not hard to fathom He’s really good. The name underneath the fireballing lefty is none other than Oakland A’s pitcher JB Wendelken. Certainly a surprise to most outside of A’s fans.
Following the weekend series against Houston in which Wendelken threw 4.1 innings, allowing 1 earned run with 7 Ks. In total Wendelken has thrown 10.1 innings, allowing just 2 earned runs and striking out 13 batters against zero walks.
Just prior to 2018’s AL Wild Card game I examined Wendelken’s sudden rise to prominence. Two things stood out then and that hasn’t changed: fastball velocity and curveball usage.
Per Pitch Info:
Wendelken’s Velocity/Usage
| Season | FA% | FA Velocity | CH% | CH Velocity | CU% | CU Velocity |
|---|---|---|---|---|---|---|
| Season | FA% | FA Velocity | CH% | CH Velocity | CU% | CU Velocity |
| 2016 | 65.4 % | 94 | 24.6 % | 83.5 | 9.6 % | 80.3 |
| 2018 | 60.9 % | 95.2 | 13.6 % | 85.2 | 25.5 % | 80.7 |
| 2019 | 53.7 % | 95.3 | 23.9 % | 86.7 | 22.4 % | 80.5 |
You can see in the graph below Wendelken’s ERA in relation to his fastball velocity:
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Each pitch seemingly has its own specialty. His fastball generates the most strikeouts (42.9%), while his curveball generates the most groundballs (83.3%). His changeup is his chase pitch, generating most of his swinging strikes (18.8%), especially on pitches outside of the zone (53.3%).
Wendelken avoids hard contact (33.3% hard-hit with 0 barrels allowed and .154 xwOBA) and he has yet to walk a batter. It won’t be long before he enters the conversation regarding Oakland’s best relief arm, if he hasn’t already.
