J.B. Wendelken is Poised to Impact AL Wild Card Game

Despite not even throwing a pitch for nearly two years Oakland A’s reliever J.B. Wendelken finds himself on the doorstep of postseason baseball.

Per Jane Lee, Wendelken is listed among those likely to comprise Oakland’s bullpen for the 2018 American league Wild Card game on Wednesday night.

This is interesting for at least two reasons. First, Wendelken is the one remnant of the Josh Donaldson trade who is likely to impact an A’s postseason game. I suppose you could make the argument that utility infielder Franklin Barreto may also be poised to make waves Wednesday night, in some capacity. But my prediction in this first point flows out of my second point, which is that J.B. Wendelken is really good.

Throughout the minor leagues Wendelken was generally a pretty good pitcher. He posted strong strikeout rates across many levels, supported by a swinging-strike rate usually around 15%. Walks, home runs, and BABIP have typically been his undoing. But, in 35.1 IP with triple-A Nashville in 2018 Wendelken suppressed home runs and walks en route to a 2.80 ERA and a late-season call-up. This was not his first call-up, however.

Wendelken pitched 12.2 big league innings in 2016 to disastrous results. In slightly more major league innings in 2018, though, Wendelken has appeared as a totally different pitcher. It is still a small sample, but a small sample that points in the right direction. He has continued to limit walks and home runs while racking up swings and misses at an above-average rate.

So what is different? Two things immediately stand out: velocity and curveball usage.

In 2016 Wendelken’s fastball generated much contact (861.%), and hard contact at that (94.1 MPH AVG. EV). In 2018 his fastball yielded far more whiffs (26.4% to 16.3% per Statcast). He also allowed an average exit velocity of just 86.2 MPH against his fastball in 2018 good for more than a 200-point drop in xwOBA.

His curveball, however, has generated much more contact, especially contact outside of the zone.

His curveball already induced 60% ground balls, so the 61.5% groundball rate this year isn’t surprising. It is even more encouraging, however, when you include the fact that he was able to shave 4 MPH off the average exit velocity against curveball from 2016 to 2018 while maintaining a worm-killing 3 degree launch angle.

His increased fastball velocity seems to be leading to a greater rate of swings and misses while the increased curveball usage seems to indicate greater reliance on the pitch that generates much soft contact on the ground.

Whatever the case, what Wendelken is doing is working. He has allowed just one run, an earned run, this season and that came in 1.1 IP back on July 24th in Texas, a game the A’s had seemingly already lost. Since then he has thrown 13.2 scoreless innings, 9 of which came against division foes Seattle and Anaheim, with 11 strikeouts, 13% swinging-strikes, and just 4 walks.

Tomorrow’s starters have been announced: Luis Severino versus Liam Hendriks, so we’re looking at a bullpen game for Oakland. It is a bold strategy, but potentially devastating if you’re the opposing New York Yankees lineup. Oakland’s back-end is anchored by Cy Young candidate (Yes, I said it) Blake Treinen as well as Jeurys Familia, Lou Trivino, and Fernando Rodney. Wendelken only adds to the depth that is the middle-relief corps already featuring Shawn Kelley, and I would not be surprised one bit if he was featured in a prominent role.