April 19, 2017

Cold Takes

How to Attack Baseball's Weakest Hitters

by Patrick Dubuque

The game of baseball moves like ivy, spreading upwards and outwards toward opportunity, consistent and chaotic. There are times in this growth where it tangles with itself, spins into contradictions. For years it drove managers to madness when their pitchers walked batters, and yet the batters themselves were encouraged by the same coaches to put the ball in play, show enough courage to take the bat off the shoulder. That seeming inequality grew as a consequence of a different priority, the valor of the productive out, available to the hitter and not his opponent.

As the culture of the game slowly grew to accept the walk and its benefits, another bias lingered: the idea that ground balls were beneficial to pitchers, while opposing hitters were often taught to swing downward on the ball and achieve that exact same result. The same cultural preference, of the ball in play (especially that vaunted achievement, the grounder to the right side with the runner on second), also promoted this strangely inconsistent set of philosophies. But batted-ball data and research has proven the benefits of not only swinging for line drives, but even putting the ball in the air compared to the grounder so long thought superior.

So now we seem to have reached a new equilibrium: pitchers trying to live as low in the zone as they can, coercing the hitters to top the ball into the ground, while batters are attempting to swing under pitches and drive them skyward. It would seem a fine equilibrium, except that these two philosophies find themselves in conflict with a third: that of Willie Mays Hayes.

While most batters may be better off shooting for the moon, or at least doubles off the wall, there’s a subset of hitters for whom the conventional wisdom demands a downward plane. The latest symbol of this mantra was Billy Hamilton, who in his first two years frustrated fans by wasting his immense speed on a 37.5 percent fly-ball rate, jogging to first as lazy flies fell into fielders’ mitts. Unlike those sluggers trying to level out their swing, men like Hamilton really did want to hit it on the ground and employ their most valuable offensive asset: their legs.

If this is the case, the question arises: which conventional wisdom is correct? Should pitchers maintain their policy of hammering the bottom of the zone against this selection of batters, or is that playing right into their bat-choked-up hands? Or are they even doing it at all? Are they challenging these batters up in the zone, forcing them into abandoning their advantageous ground balls and into a hitting style less suited for them? Let’s engage in some pleasant math and find out.

For the purpose of our study, we have to create a collection of low-power hitters to test. My first instinct was to use the batters from 2016 who had the highest BABIP on grounders, showing off their legs. This led to a top-five of Trea Turner, Billy Hamilton ... Ryan Rua, Sandy Leon, and Steven Souza. So that was out. Next was infield-hit rate: that gave us Odubel Herrera and Starling Marte, but also Kris Bryant, Brian Dozier, and J.T. Realmuto.

So I decided to forgo the speed threat and just look at the batters most likely to have the bat knocked out of their hands. So, the 20 batters (min. 300 plate appearances) with the lowest Isoolated Power:

Most, but not all, of these guys are relatively fleet of foot, although Francisco Cervelli isn’t helping by squatting in that upper-left corner. Still, it’s not a terrible collection of the right type of player without actual cherry-picking.

The next question: do these low-power hitters (LPH) see more pitches up in the zone? Yes, they do, if not a ton. Based on Statcast’s zones 1-3 (the top third of the strike zone) and 11-12 (above the strike zone), the ratios:

There’s been a growing sentiment that pitchers ought to test the top of the zone more often, not only because it leads to more strikeouts, but because of game theory. As pitchers aim more toward the ankles, hitters have begun to adjust their own strike zones lower, and prospects who thrive in such an environment are beginning to populate major-league rosters. Still, for now the pitchers who make a living are the ones who wield power (Justin Verlander), randomness (Steven Wright), perceived velocity (Chris Young), or hubris (Mat Latos). Missing bats is great, but it’s not a gamble for the faint of heart:

When hitters turn around on a pitch left up, they obviously tend to punish it. But the theory that grounders are harder to hit at belt level reveals itself to be dubious at best: batters hit them harder, too, if not nearly to the same devastating effect. Does that mean that the same applies to low-power hitters: that pitches up simply make them into slightly-less-low-power hitters?

It’s true: low-power hitters do see the same enhanced effect on their ground balls, and enjoy more success on them in general than their more cumbersome brethren. But that’s not the story. Even with that increase, they’re worse on balls in play overall. It’s not that the high heat blows the bat out of their hands, but it does lead to more high-angle, weak pop-up contact.

And of course, that’s just on balls put into play. For strikes in the upper third of the zone, whiff rates:

Being contact-oriented, our selection doesn’t strike out as much as the average batter, but it remains more prone to chasing high pitches than low ones.

Everything is a mixed strategy, and deception remains the principal tool for every pitcher not named Kenley Jansen. But even so, it would appear that even pitchers who generally ply their trade around the shoelaces might consider climbing the ladder when facing a weak stick at the plate, especially one who likes to claw their way to first via infield hit. The top of the strike zone offers all the advantages of the power pitcher with, in such cases, few of the drawbacks. It won’t stop those ground balls from happening, but it’ll make the other balls in play easier to deal with. Besides, it has to feel good to just let a two-seamer ride every now and then.

Patrick Dubuque is an author of Baseball Prospectus. Follow @euqubud
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