Gio Gonzalez is expressive on the mound, there’s no doubt about that. He tends to wear the result of the most recent plate appearance on his face. So if I told you that he threw a 3-2 pitch to Javier Báez, and followed it by looking like this:



What would you think happened? A double off the wall? A home run? Perhaps a smashed line drive that miraculously found a glove?

What if I told you that the pitch was a fastball that ended up here?



Okay, now you have a good guess. You’d make that face too if you walked Javy Báez on an uncompetitive pitch. There’s not much good to say about a pitch that missed the outer edge of the plate, per Statcast, by 13.2 inches.

Ha, I’m joking. It’s Javy Báez. That was a strikeout:

You might think, after that intro, that this is an article that will take issue with Javy Báez’s plate discipline. It is most emphatically not that. This is a paean to Báez’s singular, tremendous talent. Who else in baseball can swing at that pitch and also be a star? Who else can swing at that pitch and even be a major leaguer?

The book on Báez has always been that he has all the power in the world and none of the plate discipline. In the minors, he had unheard-of pop for an elite, up-the-middle defender — the kind of tools prospect evaluators drool over. There was just that one little thing: as his Triple-A manager, Marty Pevey, said when he was called up: “It’ll be a learning curve for Javy. He’ll want to hit every ball 600 feet. He’s such a great competitor.”

The stats and eye test were in agreement. Báez’s swing is a violent wonder, the force of a typhoon channeled through a single heartbeat of action. That aggressive swing produces great power, but with that great power comes great strikeout totals. Báez never ran a strikeout rate below 20% in his minor league career, even as he slashed .287/.346/.541 across five seasons in leagues where he was consistently one of the youngest players.

The pitch-level data wasn’t pretty either. His minor league swinging strike rate was 20.6% and his contact rate was a mere 62%. These are the kind of numbers that would be the worst in the majors even in today’s strikeout-happy game. It wasn’t a huge worry, though, because the production was still there. You could dream on Báez learning to take a few pitches (he never walked even 8% of the time in the minors), patching up his contact issues, and turning into a slugging shortstop.

What no one expected was that Báez would succeed the way he has. If you didn’t know that he finished second in the MVP race last year and had accumulated 9.6 WAR since the beginning of 2018, 12th in the majors, you might look at his plate discipline numbers and assume he hadn’t solved the issues that held him back as a prospect. Swinging strikes? His 17.9% rate is second-highest in the majors. His 67.6% contact rate is fourth-worst, and his chase rate is fifth-worst. Despite seeing the third-lowest rate of pitches in the strike zone, his walk rate is ninth-lowest among qualifying batters.

This package shouldn’t work. Mixing the swing tendencies of a slap hitter with the contact rate and power of a slugger is a recipe for disaster. Incredibly, though, it all plays. His .281/.313/.530 slash line, one of the more unusual-looking lines in baseball, has been good for a 112 wRC+. He’s launched 28 home runs a year after hitting 34. It looks impossible, looks unsustainable — and yet, for the second year in a row, it’s working.

The mathematical difficulty of being an effective hitter with such shocking swing and contact numbers is terrific. Without even considering the strikeouts and walks, there’s this: Báez makes his contact in all the worst places to put a ball into play. Take a look at how much advantage there is to making contact in the zone (or in the Heart area of Statcast’s attack zones):

wOBA By Location Zone wOBA on Contact In-Zone .409 Out-Of-Zone .297 Heart .435 Shadow .348 Chase .265 Waste .321

The takeaway is clear. Hit balls down the middle, and if you can’t do that, at least stick to the shadow of the plate. The drop from there is precipitous. For the most part, that’s exactly how the league behaves. The vast majority of contact comes in the heart or shadow:

wOBA and Frequency by Location Zone wOBA on Contact % of Batted Balls In-Zone .409 78.4% Out-Of-Zone .297 21.6% Heart .435 47.8% Shadow .348 46.2% Chase .265 5.8% Waste .321 0.1%

It won’t surprise you to know that great hitters mostly do their damage in the heart of the strike zone. The game, then, is to make as much of your contact as possible in positive locations. Báez’s game makes that nearly impossible — his chase rate is so high, and pitchers throw him so many pitches outside the strike zone, that he makes tons of contact on bad pitches. Take a look at how Báez and walking paragon of hitting Mike Trout stack up in terms of wOBA and percentage of balls in play by zone:

Báez vs. Trout by Location Zone Báez wOBA Báez % BBE Trout wOBA Trout % BBE In-Zone .491 64.6% .537 80.4% Out-Of-Zone .439 35.4% .464 19.6% Heart .543 35.9% .530 50.8% Shadow .417 51.3% .545 45.6% Chase .498 12.3% .146 3.7% Waste .438 0.6% n/a 0.0%

Both are incredible hitters on contact, naturally. But Báez puts a lot of chase and waste pitches into play, more than double the league average, while Trout has eliminated those almost entirely in favor of the heart of the plate.

That sounds bad for Báez, but it ignores the silver lining. Báez might put bad pitches into play, but he makes up for that by driving those pitches. This isn’t some weird 2019 sample size fluke, either, at least not entirely. Since 2015, the beginning of the Statcast era, he’s fourth in baseball in wOBA (third in xwOBA) when putting the ball in play in the chase or waste zone:

Best Bad-Ball Hitters (2015-2019) Player wOBA Batted Balls Brian Dozier .384 157 Eddie Rosario .378 213 Didi Gregorius .372 184 Javier Báez .357 173 Xander Bogaerts .356 196

Impugn Báez’s batting eye all you want; just understand that he’s as good as anyone in baseball at turning those cringe-worthy swings into extra bases. Is some of that lucky? Well, yeah:

Think of the skill involved in even hitting that ball, though. And don’t call this one luck — very few players even make contact with this ball, much less launch it 400 feet:

It’s not immediately obvious, but Báez’s bad-pitch contact skill makes his entire game work. One of the big problems with a low-contact approach is that two strike counts are devastating to you. Báez’s career strikeout rate after two-strike counts is a whopping 52.2%. The intuition behind this is easy — with a contact rate so low, you’re not likely to work your way into the at-bat with foul balls or turn the tables by putting something into play. He has a top 10 percent strikeout rate after 0-2, 1-2, 2-2, and 3-2 counts.

Knowing that, pitches in the strike zone are precious. Letting one go by turns a wildly positive outcome (Báez swinging at a pitch over the plate) into a tremendously bad outcome (Báez getting behind in the count). Hitting doesn’t work in stasis, of course, and so swinging at every pitch over the plate he can also leads to some bad swings.

If Báez didn’t fare so well when putting balls outside the strike zone into play, the whole equation wouldn’t work. He takes so many out-of-zone swings that the poor production on contact would sink a normal hitter. Báez isn’t normal, though — his combined production in the shadow, chase, and waste zones this year is the same as the league as a whole over the heart of the plate.

This made me wonder: should Báez actually swing more? With the caveat that we’re doing some Bad Math, let’s take a crack at it. First, we work out the wOBA value of an in-zone swing — whiffs, fouls, and contact all combined. We apply that to each count (proportionally based on the counts Báez has faced) to work out the positive value of swinging at a strike. We can then figure out, in the same proportions, the cost of taking a strike (with some smoothing so that taking a strike never increases wOBA), and compare the two.

The same process works on the ball side, only we work out the positive value of taking a ball rather than the negative value of taking a strike. Also, I made the executive decision to ignore all two-strike counts on both sides. They’re a different and special case — batters have two-strike approaches that are distinct from every other count, because the cost of taking a strike is so high. Instead, we’re wondering about the situations that lead up to two strikes.

The math, though extremely approximate, reflects what you’d expect. Every time Báez takes a strike rather than swinging at it, that costs him 79 points of wOBA in expectation in that at-bat. When he takes a pitch out of the strike zone rather than swinging at it, he picks up 57 points of wOBA. After accounting for his 36.9% zone rate, every time Báez adds 1% of out-of-zone swing rate, it breaks even with the addition of 1.2% zone swing rate.

It might not immediately be obvious, but Báez is a crazy outlier. With the caveat, again, that this is basically junk math, let’s compare it to the league as a whole. In non-two-strike counts, it costs an average player 50 points of wOBA to take rather than swing at a strike. Taking a pitch out of the zone adds a whopping 143 points of wOBA as compared to swinging. After accounting for the league zone rate, the equation looks massively different. Every time an average batter adds 1% of chase rate, he needs to add 4% of zone swing rate to compensate.

Essentially, most players face an extreme burden if they want to swing more. Turning a ball into a strike is bad enough, and actually making contact is often even worse. At the same time, taking a pitch in the zone for a strike isn’t ruinous, so the cost of the occasional take isn’t high. For Báez, neither holds. Turning a ball into a strike is bad, but putting the ball into play out of the zone (which Báez does on 27% of swings) is a strong result. At the same time, taking a pitch in the strike zone rather than swinging at it is the worst thing he can do.

Do caveats apply? You bet they do. One year of data is small sample size city, Báez’s success this year on junk is luck driven, you can’t change swing rates like that in a vacuum, so on and so on. There’s no denying that it’s somewhat true, but he’s still an extreme outlier. Run his career count-based splits rather than just this year, and a zone take costs him 87 points of wOBA while an out-of-zone take gains 103 points. He still benefits less from a good take and more from a good swing than almost anyone else.

If you think you know the book on Javy Báez, think again. You know most of it, of course. The tags, the instincts, the home runs — that’s all there. The maddening lack of plate discipline? That’s there too. Where you’re going wrong is that you wish he’d swing less. Sure, in magical Christmas land, he could just cut down on the chases and up his contact without losing anything. In the real world, though, the chases are part of a strategy. Javy Báez swings like a madman because he needs to. It sounds crazy, but it’s true.