Figuring Out Kirby Yates

I’ve gotta admit, anytime a reliever like Kirby Yates—a 30-year-old righty who hasn’t been able to stick, or succeed, on a big-league roster—comes along, I’m skeptical. For the first 10 good innings, I barely pay much attention. There has to be something wrong with this dude, and it’s going to show up soon, I think to myself. For the next 10 good innings, still skeptical. Give me another 10 good innings, though, and you’ve got my attention. And for good measure, Yates has struck out 17 while walking just two over his last 10 frames.

With San Diego this year, Yates has pitched 31 1/3 innings with a 1.72 ERA, 48 strikeouts (!), nine walks, and three home runs allowed. His 37.7 percent strikeout rate ranks seventh in all of baseball among pitchers with at least 20 innings, just behind Dellin Betances and Andrew Miller. In his prior three seasons split between the Rays and Yankees, Yates racked up 97 2/3 innings with a 5.25 ERA, 113 strikeouts, 41 walks, and a whopping 19 home runs, and in just a single inning earlier this year with the Angels, he allowed two more dingers. With the Padres, in an admittedly small sample, Yates has been able to all but eliminate his home run issues, while striking out more and walking fewer batters. That’s the pitcher’s trifecta.

The one thing that jumps out about Yates this season is his fastball whiff percentage. As I wrote about a couple of weeks back, Yates’ FB whiff rate is somehow second in the majors, behind only Craig Kimbrel, at 19.24 percent. There are at least two things that are crazy about that. For one, Kirby friggin’ Yates is second in baseball in fastball whiff rate. Most of the pitchers around Yates are certified studs (Kimbrel, Chris Sale) and/or throw really hard (Pedro Baez). Yates works in ordinary territory, around 94 mph.

If you break down Yates’ fastball even further, it compares well with Kimbrel’s heater:

Yates: 316 pitches, .172 BA, .281 SLG, .243 xwOBA
Kimbrel: 446 pitches, .109 BA, .238 SLG, .226 xwOBA

The other thing, though, is that this is a new thing for Yates. Last year, with New York, his whiff rate on the fastball was just 11.86 percent. That number is still solid—it ranked 88th in baseball among 558 regulars—but it’s a far cry from where it is now, as Yates has improved it by nearly 7.5 percentage points, from good to elite.

The big question is how? A quick look at Yates’s velocity doesn’t raise any eyebrows; it’s improved this year, but by a mere 0.23 mph. Yates’ average slider speed has increased by over a full mph, which is interesting yet seemingly leaves no clue for why his fastball is suddenly so good. Further, Yates’ overall repertoire hasn’t changed much. He’s throwing almost the same amount of four-seamers as last year, right around 60 percent, and while he’s dropped the curve entirely and swapped the changeup for a splitter, there aren’t really wholesale changes here.

Beyond the obvious indicators, there are, at least, two areas where we can identify some improvement or change. First up is Yates’ command, which we’re simply defining here as his ability to work toward the edges of the strike zone. Here’s his fastball zone profile from 2016, via FanGraphs:

And here it is from 2017:

It’s subtle, but Yates has sort of shifted his heat map down and away to righties (and down and in to lefties). He’s also hitting the edge of the zone more often this year. If you look at the boxes just inside the zone, Yates has a higher percentage of total fastballs in 14 of the 20 boxes this year. He also has fewer pitches way outside of the zone, which also might indicate better command/control. These are small changes, and I certainly wouldn’t want to draw too much from them, but they do add up when considered all together.

Perhaps more interestingly, however, is Yates’ release point. Here’s the money graph, from Brooks Baseball:

That cluster of circles on the right represents Yates’ average release point in each season prior to 2017. The one furthest to the left, naturally, is 2017, where Yates has decided to move about a foot to his right on the rubber. It looks something like this in non-graphical form:

Yates in 2016:

Yates in 2017:

Yates new position on the rubber—and in turn, his new release point—gives him a better angle to attack right-handed hitters. Whereas last year, and previously in his career, Yates was coming at righties from the opposite side of the mound, now he’s closer to releasing the ball in the right-handed hitter’s batter’s box. Combined with his arm action, which has been described as someone using a Q-tip, Yates is now even tougher for same-sided hitters to pick up. The numbers follow, despite potential sample size issues, with Yates so far posting career-bests in OPS (.472) and strikeout-to-walk ratio (6:1) vs. right handers. He still struggles against lefties (though his peripherals are better), but the improvement against righties has made all the difference overall.

Relievers are weird. Sometimes blips in performance just happen, and they’re hard to explain. In the case of Yates’ sudden turnaround, that’s probably mostly the case. It’s possible, however, that a simple shift on the rubber combined with marginally better command has transformed him from a reliever who was living up to his name (he sucked) into something of a late-inning weapon. It’ll be interesting to see if Yates can keep it up for the remainder of the year, and whether the Padres are able to deal him at the deadline.

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