2019 was not a great year for the A’s bullpen. Outside of the excellent Liam Hendriks and Yusmeiro Petit, only two other relievers threw 30 innings while having a sub 4.00 ERA. One of them was LOOGY Ryan Buchter. The other? J.B. Wendelken. Since coming back from Tommy John surgery, Wendelken has shined in the brief appearances he’s had. Now that he’s in a position to play a whole season, he’s about to break out in a big way



With a 2.55 ERA, a 3.01 FIP, and a 0.87 WHIP in 49.1 innings since 2018, Wendelken has been excellent. But those stats can be deceiving in the innings equivalent of a single season. And even then, that’s far from elite. Despite his WHIP ranking third in that time frame amongst relievers with at least 40 innings thrown, his ERA and FIP ranked 21st and 30th respectively. That’s great, but not top tier. But when you look at his advanced stats, his special ability really starts to show.



Roberto Osuna. Ken Giles. Aroldis Chapman. What do they all have in common? Wendelken had a better xwOBA in 2019 than all of them. In fact, among all pitchers with at least 100 batters faced, only 6 had a better xwOBA than Wendelken. You wanna know what else they all have in common? They all had a higher K% in 2019 than Wendelken. Wendelken doesn’t excel at missing bats, he excels at not letting the contact he gives up be any good. His average exit velocity was 86.0 MPH in 2019. That’s 1.3 MPH slower than the MLB average and lower than the average exit velocities of Ken Giles, Roberto Osuna, and Kirby Yates. He is elite. And the best part? He’s just getting better



In 2018, Wendelken used a simple three-pitch arsenal. A four-seam fastball, a curveball, and a changeup. In 2019, he added a sinker, but more importantly, a slider as well. Despite his slider making up just 4.9% of his pitches thrown, it was responsible for 6.3% of his strikeouts and was his go-to put away pitch against righties. The increased use of it will allow Wendelken to throw his changeup (easily his worst pitch, with a .257 wOBA) less, somehow making him even more deadly.



Liam Hendriks and Yusmeiro Petit may be the headline grabbers, but keep your eye on J.B. Wendelken. He’s not going to be on a lot of people’s radars, but he’s gonna be great this season. He is already elite at limiting good contact, and his strikeout rate is only going to improve.

