Trevor Williams Is Flirting With History

Trevor Williams is quite possibly the hottest pitcher in baseball, and he may end up in the record books because of it.

Williams kept rolling Wednesday, striking out a career high eight batters in his six shutout innings of work in a 2-0 Pirates’ win. He has a 0.84 ERA since the All-Star game (43 IP, 4 ER), which is the best in baseball. It’s so good, in fact, that it’s less than half of what NL Cy Young award favorites Max Scherzer and Jacob deGrom have posted. When you pitch this well for an extended period of time, you’re bound to flirt with history, and Williams is doing just that.

Over the last 100 years, there have been 20 seasons where a Pirates’ pitcher has pitched at least 60 innings in the second half of the season with a sub-2.00 ERA. It has happened just twice since 1991. Not only is Williams on pace to join that list, he’s currently leading it.

Edit: Neal Heaton, who is not listed above, had a 1.65 ERA in 65.1 innings pitched in 1989.

Bob Veale owns the club record for lowest second half ERA, recording a 0.87 ERA over 13 appearances (seven starts) in 1963. Not to take anything away from Veale, but he also allowed six unearned runs to score in that stretch. All four of Williams’ runs allowed have been earned. Veale was not totally guiltless in those six unearned runs scoring, but he was absolved from the repercussions.

Zane Smith’s strong finish in 1990 helped get the Pirates into the postseason, but he allowed almost as many unearned (9) as earned (11) runs down the stretch, saving his ERA. Third place holder Bob Moose also had five unearned runs not go against his ledger, too. So even if Williams’ misses the record for lowest ERA, odds are he still has a chance for fewest runs allowed per nine innings pitched, which is also held by Veal (1.68 in 1963).

But Williams isn’t just gunning for the Pirates’ record. He’s closing in on the MLB record for lowest second half ERA, currently held by Jake Arrieta. Arrieta crushed the hopes and dreams of thousands of Pirates fans in 2015, so how fitting would it be for a Pirate to take the title away from him?

Arrieta had a 0.75 ERA post All-Star Game in 2015. The Pirates have 29 games left to play, so let’s assume Williams will make five more starts. (It could be six, but barring another surge that gets the Pirates back into playoff contention, it makes sense to either A. adopt a six man rotation with Nick Kingham in September, B. skip a start or C. just make him go one out of every five games.) If he pitches 30 innings in those five starts and allows only two earned runs, he will finish with a second half ERA of 0.74. It’s a tall order, but he has allowed just two runs in his last four starts, totaling 26 innings. If he does that again, he’s right on the edge.

Not to take anything away from Williams, though, but Arrieta’s peripherals that season are much, much better than Williams’ are now. If you believe in regression, this might be a buzzkill.

Williams 2nd half 2018: 3.72 FIP, 1.05 WHIP, 37.2% ground ball rate, 30% hard hit rate, 8.2% K%-BB%

Arrieta 2nd half 2015: 2.00 FIP, 0.73 WHIP, 63.6% ground ball rate, 20.8% hard hit rate, 22.6% K%-BB%

Last night, Williams had a FIP of 1.99. Arrieta averaged that for months.

Williams’ 3.72 FIP since the break is 41st out of 82 qualified starting pitchers. That’s still good, especially for a guy who most figure to be the team’s number four starter. FIP is never really going to like him because he doesn’t strike out a lot of batters and walks his fair share, but he makes it work by getting soft contact. Of the 103 starting pitchers who have allowed at least 300 batted balls this year, Williams has the ninth lowest average exit velocity (85.8 MPH).

I went into what makes Williams’ an effective pitcher for The Point of Pittsburgh a few weeks ago. The short answer is “he can put his fastball on the black.” He’s still doing that, with roughly 40% of his second half fastballs being on the edge, according to Baseball Savant. 27.4% of his overall pitches since then are a fastball on the edge.

On those pitches, batters are hitting .234 with a .274 wOBA and a 32.6% combined called strike/whiff rate. He’s hitting the edge a little less frequently now than he did in the first half of the season (41.3% in the first half, 39.7% in the second), but the sheer volume he puts there works in his favor.

Putting his fastball on the edge is fueling this fantastic run. If he can keep that up, he may be making history rather than just flirting with it.