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Keep Bunting, Kolten

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Not all bunting is bad.

MLB: St. Louis Cardinals at Milwaukee Brewers Benny Sieu-USA TODAY Sports

Kolten Wong is having his best season. There’s certainly no doubt about that. He’s played nearly the entire season, he’s having his best season at the plate, and while his defense might not be literally the best it’s ever been, it’s not far off. His plate discipline is as pristine as ever, he’s increased his ISO despite fewer of his fly balls leaving the park, and he’s having his best season ever against same-handed pitching. All of these things are true, but they’re obscuring something amazing: Kolten Wong is bunting at an insane clip and making it work.

Victor Robles, noted bunt aficionado, is first in the major leagues with 25 bunts this year. He’s hilariously fast, a center fielder who has ranked around the top of the sprint speed leaderboards in his three years in the majors. He probably bunts too much, but you can at least see the thinking -- he’s struggled to make contact at times this year, with a strikeout rate over 20%, and putting the ball on the ground with his blazing speed is enticing.

Kolten Wong is second in the major leagues in bunts put in play. That might seem weird offhand, because he’s certainly not as fast as Robles. His average sprint speed, 27.7 feet per second, is barely better than league average. He doesn’t struggle with strikeouts, which limits the advantage of ending a plate appearance early. We’ve all read Moneyball, and bunts are awful. It’s an open-and-shut case, right?

I mean, look, I’m writing this article. It’s clearly not an open-and-shut case. Why isn’t it, though? Look at this dang thing:

That has to be awful! Trading an out for a base advancement in literally Coors Field? Kolten, why??? The Cardinals’ win probability declined by nearly 4.6% as a result of that play. Wong got all kinds of fist bumps and attaboys in the dugout, but the inning petered out after that, and it wasn’t even a platoon issue -- Carlos Estevez is a righty!

Okay, look, I’m not defending that bunt. That wasn’t a great one. If every single one of Wong’s bunts turned into a sacrifice, then no duh, he shouldn’t do it. What gets lost in the Never Bunt crowd, though, is that the revolution around bunts wasn’t directed towards all bunts, merely towards sacrifices. Kolten Wong is a prolific bunter, but he’s a prolific bunter *for hits*, and that makes all the difference.

Take a look at where the infielders stood just before that pitch:

Estevez made an excellent play, but that ball wasn’t far off from being a bunt single. A little more down the first-base line, a little softer, or even pushed more aggressively past the mound, and that could have been a single. That 4.6% win probability dip reflects what happened on the field, but you don’t need many bunt singles there to make this a more reasonable play. To be precise, the win probability breaks even if Kolten is successful in bunting for a single 27.9% of the time there.

When you look into it that way, the play looks a lot more reasonable. Wong is a decent hitter, after all, but he’s also a pretty good bunter. He’s attempted 22 bunts this year and reached on 10 of them. That 45.5% rate is vastly higher than the success rate he needs for the play to work in the long run. Don’t believe me?

Huh. That bunt was a slightly different situation, but it only needed to succeed 25% of the time to break even. Two bunts, a 50% success rate -- we’re doing it. In fact, let’s extend the logic to every bunt Kolten has attempted this year and tally up the win probability changes with each bunt to see how effective he’s been.

On the year, Wong has added roughly .26 wins to the Cardinals’ odds via bunting. The outcomes vary tremendously, from bunting in a run with the bases loaded (+.106 wins!) to being called out on a replay review when down one in the eighth inning (-.086 wins). That doesn’t sound like much, but consider this counterpoint: Wong has been worth a total of 0.11 wins of WPA to the Cardinals this year. In his non-bunt plays, he’s actually provided negative value!

Getting nearly .26 wins out of only 22 plate appearances is also pretty impressive. If you could make his whole season out of bunts at the same WPA rate, which of course you can’t, Wong would produce 7 wins worth of WPA per 600 plate appearances. WPA is a batting-only stat where 0 is average, so it doesn’t account for baserunning or defense and has a lower baseline, and that +7 WPA would be second in baseball to Christian Yelich on the year. Looked at in this preposterous way, Wong’s bunts are wildly valuable.

There are all kinds of problems with that approach, of course. He’s good about choosing spots where bunts are favorable, where failure doesn’t cost as much as success gains and the defense is positioned in an exploitable way. He bunts in reasonably high-leverage spots, and all of his plate appearances can’t be similarly important. If he literally bunted every time, the defense would catch on pretty quickly.

Even ignoring that, though, aren’t all the smarty-pants statistical types always telling people to avoid using WPA? Well, kind of. It’s actually somewhat useful in the specific case of bunts, because there really are times where failure is less punishing or success more valuable depending on the base/out and game state. It’s still probably not the right way to look at bunting, and maybe something like WPA/LI, which takes WPA into account but strips out the vagaries of leverage, would be better. Accounting for this still leaves Wong at +5.3 per 600 PA, which would be the sixth-best mark in baseball this year.

At this point I’m rambling, but hopefully you mostly get the point. Kolten Wong bunts a lot, and sometimes they turn out incredibly poorly. They also often turn out incredibly well, though, and that’s easy to lose in the moment. Here are some other data points that make the bunts look even better that I’ve been saving for the end of this article: Wong is actually faster down the line to first than Robles on average, thanks to being a lefty. He has a .514 wOBA on bunts this year. He’s bunted more against lefties than against righties despite overwhelmingly facing more righties than lefties, which means he’s beating his platoon splits by bunting. You get the idea.

Lots of bunting is bad. We all saw Brad Pitt yell at some random guy about it (truth time: I’ve never actually seen Moneyball, though I’ve read the book). We sabermetric types love to dunk on dumb decisions, and committing the sin so cardinal a book was written about it is the most obvious one of all. When I started looking into this, I expected to see that Wong was bunting too often. He’s not, though! He’s bunting well, and he should maybe even bunt more often. Keep that in mind the next time you want to use some pearl of wisdom without delving into the circumstances.

All stats are current through Thursday’s games. Dangit if Wong didn’t go ahead and bunt for a hit again last night. Add another .068 WPA to the ledger.