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Piratesguide Excerpt: Mythbusting Trevor Williams

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MLB: Pittsburgh Pirates at Milwaukee Brewers Patrick Gorski-USA TODAY Sports

The following is an excerpt from PIRATESGUIDE 2019, a PIttsburgh Pirates season preview book from myself and Alex Stumpf here at Bucs Dugout, among others. If interested, you can read more studies like these and much more by ordering the book from Amazon. It comes in paperback with prime shipping, or e-book!

As a thought exercise, let’s assemble the perfect starting pitcher. Or, as close as we can get to it, anyway.

What’s the first thing you’d graft on to this Frankenstein’s monster of a hurler? Would you go straight to velocity and gift him Noah Syndergaard’s four-seamer? Value breaking stuff? How about a Clayton Kershaw in-his-prime curveball? Would you rather select pinpoint Maddux-esque control or would you be lured astray by Randy Johnson’s strikeout ability? Thinking long-term now, how about the longevity and overall whimsicality of the great Bartolo Colon?

As fun as it is to think about what a “perfect pitcher” can take from these names and so many more in the rich history of baseball, at the end of the day, the perfect pitcher needs just one ability: getting hitters out.

Piratesguide 2019: Available now at Amazon

And no one did that on the 2018 Pirates as the season wore on better than Trevor Williams. Over nine magical starts from July 11th to September 3rd of last year, Williams allowed just four earned runs across 54.1 innings. His outings became appointment viewing for a club that – at the time this stretch started – saw its fans’ interest swiftly fading. This masterful stretch was part of a second half that saw Williams put it all together. His final marks of a 1.38 ERA /1.07 WHIP and 2.75 Strikeout-to-Walk ratio after the All-Star break showed a pitcher who may have pitched his way into being the best version of himself.

No, Williams will likely never have a defining characteristic that folks writing baseball analysis in the future can glom onto for a catchy intro. But, yes, he did learn how to get Major League hitters out on a consistent basis in 2018. That much is clear.

Yet to hear some tell it, Williams is a sure-fire regression candidate. “There is no way that he can do it again,” they proclaim. It was all smoke and mirrors, you see. While the podcast host who moonlights as a pitcher might still be an effective back of the rotation starter in their eyes, this contingent treats that second half as a mirage rather than salvation for a pitcher who was traded for an executive.

Are they right? Are they wrong? The jury is out, but we can venture an educated guess by mythbusting the common misconceptions surrounding Williams.

Myth #1 – His lack of a four-seam velocity disqualifies him from being consistently effective.

Yes, Williams does not have blazing stuff – his four-seamer averaged just 91.80 mph in 2018 while his sinker came in at 89.37. Yet there have been many that have found effectiveness with less. Williams clearly fits that mold.

Among all starting pitchers in 2018 that threw a four-seamer between 90 and 94 mph in 2018 – while facing a minimum of 250 batters – Williams carried the best wOBA against those four-seamers at .277. If we apply those same parameters to his sinker/two-seam fastball, Williams clocks in at sixth best overall with a .290 wOBA. While not a classic out pitch by any means, it is worth noting that Williams rang up 71 of his 126 strikeouts on a four-seamer.

By all accounts, Williams’ four seamer is unremarkable in many ways. We’ve mentioned the lack of velocity, but we can’t forget that the pitch also lacks deception with a 16.98 percent whiff per swing rate and carries below-average spin of 2,172 rpm. He works the edges of the strike zone well enough – 17.9 of his four-seamers thrown on the edges result in a strike (the league rate in this regard is about 18.5 percent) – but the real proof in this pudding comes from batted ball data.

Among all starting pitchers who faced at least 100 batters in 2018, Williams ranks fourth in percent of four-seamers hit for “poor” contact as per Statcast. 65.7 percent of his four seamers that were put in play were hit poorly, regardless of location, count, situation or any other filter.

Beauty is in the eye of the beholder as they say, but anyone who is beholding the effectiveness of a four-seam fastball must recognize the allure inherent in Williams’ offering, even if they must squint to see it.