STATE COLLEGE, Pa. -- A word of warning: don't try to make sense of Trevor Williams' results since returning from injury on June 19. To do so is folly.
Williams, so so good over the last half of 2018, was rocked again Sunday to the tune of eight earned runs, including three home runs. That's eight home runs across four starts since his return.
Before his side was injured May 16, Williams was turning in another typical season of solid starts. He had gone at least six innings in each of those eight outings, giving up more than 3 runs only twice.
Before we get into what's changed, let's see if we can find any sanity in Williams' season-long peripherals, as compared to his watershed 2018.
OK, so we have a shred of logic to go on from this data, but not much. Williams famously used the edges of the strike zone more than any other Pirates starter last season, to the tune of 68.9 percent. He's continuing to use those edges in 2019, with a 67.8 percent clip. Yet, his wOBA on those fringes of the zone has seen a steep increase. Let's look deeper at that.
First, a look at Williams' overall pitch selection year-over-year, regardless of count or location:
Williams has leaned into his four-seam fastball usage a bit more, while trying to emulate his rotation mates with their sexy swing-and-miss stuff. And that approach has worked in a way. At least, it seems so. The slider had a whiff-per-swing rate of 22.6 percent before June 19, an a 27.3 percent rate since.
Sounds great, right? Well ... not exactly.
Again, Williams has looked like an entirely different pitcher since returning. His fastballs have been punished to the tune of a .538 wOBA/.351 xwOBA, compared to prior rates of .245/.282. This has caused him to come into the zone with his slider a bit more -- specifically, a 47.6 percent rate since coming back against a 39.5 percent rate prior. He is currently saddled with a .452 xwOBA on sliders that find the zone since returning. That number, so far, has not hindered him much, as the pitch has a slugging-percentage-against of just .389 on ones that find too much of the dish.
No, since June 19, it's those darn fastballs that are to blame, with a .900 slugging percentage when they find the zone. For reference, hitters could only manage a .333 mark against him before his injury. And here's where things get weird: the pitch is virtually unchanged year-over-year. Velocity is up and the pitch is moving more than ever, with fantastic late life at times.
But when it gets tagged, boy does it get tagged.
Here's an example of one such fastball, with Williams trying to replicate what he did so well last season by finding an edge:
For Trevor Williams to approximate the incredible run he had over 2018's second half, he'll likely need to incorporate his changeup in better spots than he is currently. Last season, when ahead in the count, Williams pulled the string 16.2 percent of the time after a fastball. This season? Just 11.2 percent. That pitch is still quite sturdy on the edges with only a .251 wOBA against. One wonders what the hesitation is in regards to using it right after the heat.
Until his fastball comes around, Williams will have to use every one of his tools to get outs, limit runs, and pitch deep into games.
MORE MOUND VISIT
July 12: What's eating Crick's slider?
July 11: Frazier’s back, maybe
July 9: Myth-busting the first half
July 8: A four-seam heavy first half
