Pittsburgh Pirates: Is There Something More to Trevor Williams’ Struggles?

After a historic second-half of the 2018 season in which he posted just a 1.38 ERA in 71.2 innings, Pittsburgh Pirates’ starter Trevor Williams looked as if he could be one of the best pitchers in baseball. In 2019 he not only failed to improve, but he struggled enough to put his future in doubt.

The Pittsburgh Pirates entered the 2019 season with the belief that their strong pitching staff would lead them to the post-season again. While injuries and struggles have plagued the Pirates pitchers all season, it doesn’t make the future look any less bleak. Especially when one of those pitchers was among one of the best pitchers in baseball just a season ago.

Earlier this year, I wrote about Trevor Williams and his potential battle with the regression bug, mainly by emphasizing the difference between his ERA & xFIP:

"Williams’ ERA- was 79 and his xFIP- was 112, which is a 39 point difference. While that difference isn’t as large of a margin as the average of Sullivan’s study, there is plenty of reason to believe that his ERA should regress. After all, Williams posted a 4.07 ERA in 2017 with a lower xFIP- of 104."

Not only did Williams regress, he did much worse than my modest projection of posting an ERA around 3.90-4.00. This season, Williams had a 5.38 ERA over 145.2 innings, which ranks 6th worst among pitchers with at least 130 innings pitched.

Williams’ peripheral stats declined as well.

Last year he posted a 3.86 FIP and a 4.54 xFIP. This season they fell to 5.12 and 5.25 respectively. His ground ball rate dropped from 43% to 37%, which is coupled with an increase in his HR/FB rate from 8% to 14.5% this season.

Now, it should be considered that WIlliams went on the injured list early in the season with a side strain. This placed him on the 10-day IL at a time when he posted a 3.33 ERA to go along side a 3.41 FIP and 4.54 xFIP. That’s much similar to his line last year of 3.11/3.86/4.54. His HR/FB was only 7% and hitters hit grounders 40% of the time.

Since the injury, Williams just hasn’t looked the same. After returning, he posted a line of 6.458/6.14/5.68 to go along with a 35.5 GB% and a 17.8% HR/FB. Was he possibly still dealing with side issues? His pitch velocity and usage did not changed much, but that doesn’t mean he wasn’t dealing with issues.

According to Baseball Savant, hitters slugged .527 against Williams’ fastball this season compared to .338 last season, so maybe hitters have finally figured out his best pitch. Williams has developed a strong slider, posting a .291 xwOBA and a 31% whiff rate, but his struggles with his fastball could be a major problem. His other pitches haven’t been very good either.

It seemed obvious that regression would soon come to Trevor Williams, however, his struggles in the second half may indicate something larger is at play. Whether its that hitters have just found out his fastball or his early season injury is still affecting him, it’ll be worth watching how Trevor responds in the off-season.

A healthy off-season is much needed for Trevor and pretty much the rest of the pitching staff heading into next season. If Trevor can return as the top 25 pitcher he was just a season ago, that would be a huge change of fortune for the Pirates who, after a terrible second-half performance, will be looking to fix the pitching problems that have plagued them this season.

Trevor Williams has been one of my favorite Pirates over the past couple seasons due to his amusing antics and all-around professionalism and compassion. I would love to see a return to the dominance he had in 2018, where he truly flourished in the second half. Perhaps Trevor just needs a healthy off-season to return to that, so there is hope.