Do Sluggers Really Swing More on 3-0?

According to Baseball Prospectus’s set of Run Expectations matrices, when Evan Gattis stepped up to the plate in the fifth inning of Houston’s June 27 game against Oakland, the Astros were expected to score an average of 2.26 runs (taking the three-year mean from 2014-2016). The bases were loaded for Houston, which was down 1-0, and in over four innings of work thus far, opposing pitcher Sean Manaea had already walked a trio of batters, including the previous hitter. Against Gattis, Manaea had gotten himself into even more trouble, with the first three pitches missing outside. On the fourth pitch, the Astros’ mighty slugger, evidently with the green light to swing, did exactly that, with the following result:

By the time Houston’s next batter, Brian McCann, stepped to the plate with two outs and a runner on third, the Astros were only projected to add an average of 0.352 runs to the one that had already crossed home plate. As it turns out, McCann grounded out to shortstop, and the ‘Stros ended up scoring only one total run from a bases loaded, no-out situation. As calculated by Baseball Reference’s wWPA metric, Gattis’s run-scoring double play actually decreased the team’s chances of winning by ten whole percentage points, and they’d eventually drop the game to Oakland, 6-4.

To an innocent MLB.TV subscriber who happened to see the preceding events play out, it seemed an odd scenario for Gattis to get a 3-0 green light. After all, Manaea had been relatively wild up to that point in the game, and he’d even walked the previous batter, Carlos Correa. It got me thinking about league-wide trends on 3-0 swings, and thanks to Baseball Savant, there’s a wealth of 3-0 count-related data to pore through.

First, there are some interesting trends involving the overall league frequency of 3-0 pitches and swings. Using R’s ggplot data visualization package, I graphed the frequency of pitches in a 3-0 count, relative to pitches in other counts, as well as the swing rates on those pitches:

Batters are swinging more and more at 3-0 pitches, even though those pitches are steadily becoming less common. In a league that’s been increasingly prioritizing power, it’s possible that batters are responding accordingly to the fact that they know, with a high degree of accuracy, what pitch they’re about to see. Of the 4,721 3-0 pitches through the 2017 All-Star break, nearly 87% of them were categorized as some type of fastball, as categorized by Baseball Savant.

But which batters are most frequently given the go-ahead to swing away in a 3-0 count? Common perception is that the more powerful the batter, the more likely he is to be given a green light from his manager; this would certainly fit the Gattis anecdote above, and a 2014 Beyond the Box Score article noted that “the guys who swing 3-0 are sluggers,” citing Albert Pujols and Ryan Howard’s high swing numbers as evidence.

I graphed the number of each batter’s 2016 3-0 swings against his 2015 SLG, limiting the data set to batters who saw at least ten 3-0 pitches to avoid outliers (among these outliers: pitchers Jose Fernandez, Jake Arrieta, and Madison Bumgarner, each of whom swung at at least one 3-0 pitch). If powerful hitters really do swing more often on a 3-0 count, we’d expect to see a positive relationship in the data. Of course, this analysis does come with the caveat that batters, once given the freedom to swing, still can choose not to, and pitchers are likely less inclined to groove a 3-0 fastball to hitters they know are more likely to punish them for doing so.

As it turns out, the five batters with the highest number of swings were all notable sluggers — Joey Votto (17), David Ortiz (14), Mike Napoli (14), Giancarlo Stanton (14), and Josh Donaldson (12). Take a look at the below graph:

Evidently, there is some sort of relationship between the number of 3-0 swings a batter takes, and that batter’s power. It might, however, make more sense to look at the rate of 3-0 pitches a batter swings at, rather than the absolute amount. After all, one might expect a batter with a high slugging percentage to have (a) more at-bats that reach 3-0, as the pitcher would be more likely to pitch around him; and (b) more at-bats total, as his high slugging percentage would warrant more frequent appearances in the starting lineup.

As illustrated below, I charted each batter’s 2016 3-0 swing rate against his 2015 SLG:

Interestingly, there doesn’t seem to be much of a correlation between a batter’s prior-year slugging percentage and his current-year 3-0 swing rate, although we should acknowledge the small sample sizes of the pitches driving each individual batter’s swing rate. (For what it’s worth, I performed the same analysis using ISO, rather than SLG, and limiting the data to batters who saw at least twenty 3-0 pitches, rather than ten, and got very similar results.) A list of the top batters by swing rate, again including only those batters facing at least ten 3-0 pitches, doesn’t exactly comprise an All-Star team, either — while Stanton and Pujols are numbers four and five, respectively, the swing leaders also include Rickie Weeks Jr. (1), Wilson Ramos (2), and Hernan Perez (7).

There’s also not much reason to believe that the batters who do swing most often at 3-0 pitches tend to make any better contact than those who don’t. The following chart compares batters’ 3-0 swing rates with their 3-0 swings’ expected wOBA, and, as the R^2 indicates, their relationship is nonexistent:

Finally, let’s observe the relationship, if there is one, between 3-0 swing rates and player age. Sam Miller, now an ESPN writer, penned an excellent 2014 article for Baseball Prospectus in which he listed a few managers’ respective 3-0 strategies. Ned Yost, for example, did only grant the green light to the most powerful members of his lineup — but only with one out, and only in certain game situations. On the other hand, Davey Johnson, then in charge of Washington, was far more liberal. My hunch, though, is that managers are generally most inclined to let their veteran players swing away. What follows is a plot of 2016 3-0 swing rates against player age:

As it turns out, there’s not much of a reason to suspect a relationship here, either. But again, each analysis comes with the caveat that batters don’t have to swing when given a 3-0 green light, and some batters may not even need an explicit green light signal to know that they’re allowed to swing.

Even so, we can conclude the following: although 3-0 counts are occurring less often, relative to other counts, batters are swinging at a steadily increasing rate — perhaps to take advantage of the grooved fastball they’re virtually guaranteed to see. Pitchers, therefore, shouldn’t necessarily take for granted that the hitter won’t swing at their 3-0 pitch, and shouldn’t necessarily expect younger and/or less powerful hitters to refrain from swinging. And while batters’ wOBA on 3-0 is significantly higher than on any other pitch, in a stark contrast to common perception, it surprisingly doesn’t appear that powerful batters make any better contact than weaker hitters. I may eventually replicate this analysis with a focus on different game scenarios — for example, whether sluggers behave differently in blowouts, or in high-leverage situations — but for now, I’ll definitely be paying extra attention next time I see a power hitter or veteran up with a 3-0 count.