PITTSBURGH — Trevor Williams has been something of an enigma in 2018.

If you ask an average fan, Williams might be the Pirates best starting pitcher, with a 2.72 ERA entering Sunday.

If you ask a much more sabremetrically inclined one, Williams’ 4.88 xFIP is a sign that he’s very unlikely to be able to maintain his hot start.

But sometimes stats like FIP and xFIP don’t really tell the whole picture when it comes to an individual pitcher. Because they exclude and normalize balls in play, they minimize the very one thing that Williams is usually trying to do the most: get weak contact.

In the past, Williams’ two-seam fastball has been his primary weapon in getting weak ground balls. This year, he’s used his changeup to get weak fly balls. But either way, Williams’ goal on the mound most nights is to get weaker-than-average contact.

So is there a way to measure how successful he’s been in that regard and normalize it in some fashion? Sort of.

Let’s start off with his xFIP. The difference between FIP and xFIP is that xFIP normalizes a pitcher’s HR/FB rate by assuming that it will eventually revert to league average. The current league average is 12.5 percent and Williams has allowed just 7.9 percent of his fly balls to leave the ballpark.

The concept of xFIP is based on the idea that pitchers don’t have a lot of control over which fly balls leave the park, but that isn’t entirely true. Pop ups, after all, are fly balls that are almost always out and other weakly hit fly balls have little chance of going for homers.

In 2017, Williams finished with a 9.9 percent HR/FB rate, and his career total is 10.6 percent. That’s still not a huge sample — Williams has thrown just 216 career innings — but it’s reasonable to think that Williams may be able to maintain a sub-league-average HR/FB rate.

What about Williams’ ability to get soft contact?

On hits that are classified as soft contact, Williams’ opponents have a .114 BABIP. On hits that are classified as medium contact, hitters have a .237 BABIP, and with hard contact, they have a .333 BABIP.

So clearly, soft contact goes for a hit less frequently, as one would expect. But how do those numbers line up with averages? This season’s league average BABIP for soft contact is .152, medium contact is .245 and hard contact is .453.

Williams’ overall BABIP (.226) is low, but not obtrusively so. But it’s clear where the difference is. It’s not that Williams is getting a lot more outs from his soft contact. It’s that much less of his hard contact is finding the ground.

He’s not getting soft contact at a higher-than-average rate, either, but he is getting hard contact at a very low rate. Williams’ 26.3 percent hard-contact rate is eighth in the majors. Some of the pitchers above him are Jake Arrieta, Jacob deGrom, Justin Verlander and Noah Syndergaard.

Obviously, that’s good, and it also means that while the wide gulf between Williams expected and actual BABIP on those hard-hit balls remains, the fact that he’s getting so many fewer of them than everyone else means that Williams should have a lower-than-average overall BABIP.

So, Williams’ BABIP is low, which is helping to inflate his FIP, and his HR/FB rate has been historically low, meaning that xFIP may be overcorrecting. It still appears that Williams is due for at least some regression, but it might not be the huge reckoning that the first glance at the figures suggests.

Of course, none of that explains why Williams — who possesses as average fastball velocity of just a tick over 92 MPH — has been able to limit hard contact. Not to dismiss Williams’ ability, but isn’t it a bit of a jump to suggest that he should or even could be as good as Arrieta, Verlander and a guy they call Thor?

Whenever such a discrepancy exists, it’s a bit unsettling to not at least have a theory as to why Williams has been able to suppress hard contact. Otherwise, it could very easily be a random whim of the vagaries of a two-month sample size.

Pirates manager Clint Hurdle said that he’s been impressed by Williams’ “feel-to-pitch,” the ability to make good decisions on the mound and stick with a game plan.

By introducing the change-up as his primary off-speed pitch, Williams has already
accomplished one thing when it comes to being able to stick with a game plan: he now can execute multiple ones.

Williams’ modus operandi coming up was a classic sinker-slider pitcher that used his two-seamer to get ground balls and used his slider as a swing-and-miss pitch. The slider is still his best whiff option, but the introduction of his change-up and curveball as a weak contact pitches with air out tendencies has allowed him to take advantage of ways to attack hitters that weren’t always open to him in the past.

Here’s Chicago White Sox manager Rick Renteria, before his team faced Williams last week on playing the matchup game, given the amount of information that’s available to modern pitchers and hitters.

“There’s so many things out there today to study and analyze why a (hitter) is having success,” he said. “So, they break it down, every hitter. Every hitter can be broken down. It’s a matter of trying to clearly see what kind of approach you’re going to have against your opponent. I think its a cat-and-mouse game. It always has been and always will be, there’s just much more information available for guys to understand.

“Ultimately, it comes down to execution. If a hitter gets a good pitch to hit, he stays in the zone, takes a good swing and he’s able to make good contact, he’s got a chance to have success. If a pitcher knows that’s he’s got to make the type of pitch that he has to make, if he executes, he has a chance to dominate the hitter. The reality is that hitters are looking for mistakes.”

Mistakes, of course, come in many fashions. There are balls just left too far up in the zone or that catch too much of the plate. Williams had a couple of those in Sunday’s 8-5 loss to the San Diego Padres, particularly a scalded home run by Christian Villanueva in the fourth inning. Those are pretty easy to diagnose from a pitcher’s standpoint.

But there are different, more subtle mistakes. If the game plan is to throw a hitter a first-pitch inside fastball and he hits the first one, what happened? Was it a lucky guess? Was it an imprecise pitch? Or is the game plan wrong? Being able to make those diagnoses in-game is what Hurdle is talking about when he talks about pitchability.

There’s also the matter of having the proper stuff to make a successful plan of attack in the first place. Take Richard Rodriguez. Rodriguez is having a fine season out of the Pirates’ bullpen, but he basically only has two weapons: a high fastball and a low curveball.

If the game plan is to throw a two-seamer away, a change-up or a slider, Rodriguez is out of luck, because he doesn’t throw any of those pitches.

But Williams does. He has a four-seam and two-seam fastball that he can throw to any quadrant of the plate. He’s always had an above-average slider and now he has a changeup that he’s using even more frequently than the slider and a curveball that he throws just often enough to be able to have it if he wants it.

There aren’t many pitchers with more to their arsenal than that, and it’s allowed him to be flexible with his in-game approach. Against the White Sox, Williams got 11 fly balls outs compared to four ground outs. That was by design as he used his changeup and elevated four-seam fastball to get the fly-ball hunting White Sox to pop the ball up.

“I think he goes with what he’s got,” Hurdle said. “He’s got a real good read on feel to pitch. Matched up against that team, he used the stuff that he had. He used his elevated fastball (Tuesday) more than he had in the past, by design. It goes back to him watching, him studying, him doing the homework beforehand.”

It makes sense that Williams’ well-rounded arsenal, overall level of precision and feel to pitch could be a cause for hitters being unable to regularly barrel the ball up against him. It could also just be random noise over a fairly small sample size.

But there’s at least the makings of a theory there that fits: Williams’ ability to minimize the impact of hard contact means that fielding independent stats like FIP and xFIP are going to underrate him, and that the big reckoning that appears on the surface might not ever come.

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