Tony Zych and the Front Door Slider

marc w · April 19, 2016 at 12:15 pm · Filed Under Mariners 

Let’s get this out of the way early: it’s still April. Numbers are still bouncing all over the place, and a good game can totally change a player’s “season” averages, because the seasonal sample is still tiny. I get that, you get that, but we can’t just shut the blog down until the All-Star break. We can look at things, and muse on them, all while keeping in mind that they could be the product of small-sample gremlins, dumb luck, or however you personify the concept. Ok? Great, let’s talk about Tony Zych, one of the most intriguing pitchers on the M’s. As Jeff Sullivan wrote at Fangraphs, he came from nowhere to become one of the M’s secret weapons with a lively fastball and a weirdly great slurvy slider. A lot of the time, the term “slurve” is a disparaging comment on a breaking ball’s inability to be either a true curveball, with topspin and downward break, or a slider, typically thrown harder with later and less downward break. Sometimes, though, being unlike traditional or textbook examples of a pitch works really well.

To further set this up a bit, we’ve talked a lot about how the best pitches in baseballs induce a lot of swings on balls – if you get a batter to swing at a pitch outside of the strike zone, good things will generally happen. For Hisashi Iwakuma, for example, the splitter gets plenty of whiffs despite the fact he throws it below the zone all the time. And if they DO make contact, the quality of that contact is generally poor, leading to a lot of ground balls in Kuma’s case. Not everyone has a pitch that does this, and certain pitch types are better for the whole swing-at-bad-balls gameplan: change-ups and splitters work well, while, say, curves generally don’t. That doesn’t mean curves are bad, obviously, as there’s an obvious inverse strategy: get batters to *NOT* swing at strikes. Curves are the classic example – think of The Bartender practically tearing Alexei Ramirez’s knee ligaments a few years ago. That’s great, but Tony Zych doesn’t throw a curve, right?

Batters swing at pitches within the strike zone around 2/3 of the time. In 2015, the average was 66.9%, and it was 65.7% the year before. In the early going in 2016, it’s dead on 66%, so it’s pretty stable. If you sort pitchers by the zone-swing%, you get this list, and see Zych at #3, with just 41.5% of his pitches in the zone inducing swings. How’s that possible? At first, I thought it might be his fastball’s strong horizontal run – maybe batters just leave it alone thinking it’ll be a ball, or just because their gameplan is to make Zych prove his command’s good enough to get strikes with it. Lots of first-pitch fastball takes? That’s a piece of it, perhaps, but the story here is that slurvy breaking ball. The heatmap for it is pretty conventional, with a big red spot down and away to right-handers. The swing rate chart looks similar, with pitches away to righties/in on lefties generating lots of swings. The flip side of the that, and it’s easier to visualize this in this chart focusing on righties, is that righties generally aren’t offering at sliders on the inner half, or really, at anything BUT those outside sliders. This year, it’s almost comical – he’s thrown 18 sliders within the zone, but not on the outer third to righties, and they’ve offered at 3 of them.

This is the definition of a tiny sample, and he’s due some regression here, as big leaguers generally don’t take pitches, even breaking balls, middle-middle. But you can see the contours of a successful approach here, and it’s something we saw in his very first MLB at-bat, with the first slider he threw. Jeff linked to this in his post, but here, take another look. The key is that this pitch is starting right at a right hander’s hip. A slider with “normal” horizontal break might not hit the batter, but it wouldn’t get all the way back to the strike zone. Zych’s horizontal break is just over 2 standard deviations from the league mean, so it’s probably understandable that most hitters – almost all of whom haven’t faced him often – assume the pitch will stay inside.

Zych’s part of the reason why the M’s are off the charts as a *team* in zone-swing%; Felix, for all of his control problems, looks excellent so far in this metric, too. I don’t know that Zych can keep this up once hitters have seen him 3-4-5 times, but for now, it’s kind of amazing to see, and as that leaderboard shows, some of the best relief pitchers in the game make their living this way. At #2 on the list was Andrew Miller, and his teammate Dellin Betances was #5. Betances has that huge curve, so that makes sense, but Miller’s a FB/SL guy like Zych, and he led the league in fewest strikes-swung-at last year (Dellin Betances was #3, right behind the M’s Carson Smith). Miller uses his slider somewhat similarly, with lefties not swinging very much at “front door” sliders – pitches that break right over the inside corner, while hacking away futilely at low-and-away sliders. Miller’s command is such that he can throw those same pitches to *right handers* and back door them, so that’s why he’s one of the best relievers on the planet. Still, not a bad guy for Zych to emulate.


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