The Most Feared Hitters in Baseball — And Jacob Stallings

If you’re looking for a way to assess pitchers’ respect for hitters, staying away from the zone is a decent proxy. Pitchers know Mike Trout has power, so they try to keep the ball away from him. When an opposing pitcher steps up to bat, it’s the opposite: it’s time to flood the box with impunity, because they’re unlikely to do any damage even if they do make contact.

You could, if you were so inclined, get even more specific. Forget the strike zone: let’s focus on the heart of the plate, middle/middle. It’s not a sign of disrespect to throw Cody Bellinger a slider on the black, low and away. Lobbing a meatball down Main Street? That’s really what we’re after. While we’re at it, let’s adjust for context, in a crude way, by looking only at 0-0 counts. Throwing down the middle on the first pitch of the at-bat doesn’t make sense against a power hitter — you can only get one strike if they take, while bad (for the pitcher) outcomes abound when they swing.

Indeed, if you’re looking for a list of batters who pitchers disrespect, the highest middle/middle rates on 0-0 counts (minimum 50 PA) really paint a picture:

Yeah, it’s okay to throw down the middle to Clayton Kershaw and Jack Flaherty. Shocking! Raise the minimum PA to 200 to weed out pitchers, and the list still makes sense; Leonys Martin and Cheslor Cuthbert see the most strikes, with Austin Barnes a close third. Limited power, the threat of a walk if they get ahead in the count; winging it in there and hoping for the best seems like a reasonable plan.

On the other side of the spectrum, Trout elicits respect from his opponents. He has the 12th-lowest middle/middle rate on 0-0, and the list really is peppered with great hitters:

Trout. Bellinger. Christian Yelich. Heck, even small-sample phenoms like Aquino and Tauchman make sense, as does Josh Bell given his torrid start to 2019. All alone, and in front by a lot, is Jacob Stallings.

Wait, uh, what? Stallings is a career .268/.327/.370 hitter with a 7.4% walk rate. His ISO sits at an unimposing .101. He should be on the other side of the list with Barnes and Martin. Not bad hitters, per se, but hitters who pitchers attack in the zone.

This has to be some kind of fluke, right? Focusing on the very center of the zone must have missed some pitches that were middle-ish but not quite in that very middle box. Pitchers aren’t staying away from Stallings! We just need to zoom out and look at zone rate, pitches that are in the strike zone, on 0-0. Did that fix it?

Well, kind of. Stallings didn’t have the lowest first-pitch zone rate in baseball last year. But he was in the 22nd percentile, one of the top quartile of most avoided hitters. Yordan Alvarez saw a higher proportion of first-pitch strikes. Juan Soto and Max Muncy had similar zone rates. How can a defense-first catcher merit the same treatment as those thumpers?

As is often the case in these “look at this weird guy leading the league” articles, it’s all in the framing. You see, up at the top of the article, I primed you to think of zone rate on the first pitch of a plate appearance as a proxy for fear and respect. Good hitter? Stay away. Pitcher hitting? Go for blood. I also primed you to think of middle-middle rate as a proxy for zone rate, which it certainly isn’t. Stallings sees a below-average amount of strikes on the first pitch of an at-bat, but he’s not extreme.

First pitch behavior doesn’t exist in a vacuum, however. What might happen if the batter swings is a key factor in determining what a pitcher should do, but the batter also has plenty of agency in the confrontation. If a batter doesn’t swing on 0-0, that’s a relevant data point. Against a fearsome hitter who rarely swings on 0-0, stealing a strike with a get-me-over breaking ball or sneaky fastball might be worth the risk.

On the other hand, why throw a meatball to a batter with a swing-first approach? Javier Báez, to use the archetypical example, isn’t up there to take a walk. He’s swinging out of his shoes at the first opportunity. Why open yourself up to this?

Add in this datapoint, and the stereotypical lightbulb goes off. Pitchers have to juggle multiple considerations when dialing up their approach against a given hitter. You can be aggressive and powerful or weak and passive, sure. But some hitters are aggressive and weak, or passive and powerful. Seeing all the pitchers in the most-strikes group was a trick — they’re mostly passive slap hitters. Maybe we should take swing rate into the equation.

Stallings, as it happens, falls into the aggressive but light-hitting group. He’ll take a hack at a pitch outside of the zone, even on the first pitch: his 22.5% first-pitch chase rate is in the top 10% of all hitters. Missing the zone on the first pitch against Stallings is far less costly than it is against, say, Trout, who chased a ball on only 5.1% of his 0-0 counts last year. Báez, on the other hand, checked in at second in baseball with a 31.5% first-pitch chase rate.

Let’s ask a separate question, then. After adjusting for first-pitch chase rate, which batters do pitchers most fear? There’s surely a rigorous way to ask this question, but rigor is overrated: instead, let’s simply regress first-pitch chase rate against first-pitch zone rate and see what shakes out.

First things first: batters who chase more often see a lower percentage of first-pitch strikes. Well, yeah. That seems logical. The new leader in most strikes seen, relative to chase rate, is Jeff Mathis. He chases a lot, which would normally mean pitchers stay away. He’s Jeff Mathis, though. Pitchers don’t stay away. Why would they? Good start for our new fear gauge.

Who do pitchers stay away from most relative to their swing rate? Well, Jacob Stallings isn’t making this list, let me tell you:

Now we’re talking! This is a checklist of big beefy sluggers, plus freaks of nature like Yelich who punch above their weight. Heck, Daniel Vogelbach checks in at 11th. But there’s a problem with this data. Take a look at those forecasts. A little clustered together, aren’t they? That’s because chase rate isn’t particularly correlated with zone rate on first pitches, even though we’ve got the Javy Báez example that makes so much sense in our minds. Overall swing rate isn’t much better. In fact, here’s the list of lowest first-pitch zone rates, period, without any adjustment for batter behavior:

Not so different, are they? That’s because of the low correlation — our “prediction” for a player’s zone rate comes out reasonably close to the league average for every player. Let’s try something different. Rather than using swing rate as a predictor, let’s use power instead. Here are the batters who see the lowest zone rate on first pitches, adjusted for their isolated power in 2019:

Better! Yonder Alonso and Tyler White should see a lot of pitches in the zone, because they weren’t doing much damage when they put the ball in play. Aquino still saw few pitches in the zone — but he should have! He’s fearsome. And Joey Gallo, who featured prominently on the previous list, falls off completely. He’s not seeing many strikes, and that’s completely reasonable. Trout, in fact, sees more first-pitch strikes than you’d expect based on his ISO. He’s simply so patient, and so likely to walk if you pitch him passively, that pitchers are choosing the lesser of two evils and coming into the zone. Maybe we were on the right track all along in considering power.

In the end, this wasn’t really a meditation on Jacob Stallings. Sure, he didn’t see many pitches down the pipe in 2019, but his overall zone rate wasn’t completely wild. I think, however, that there’s something to learn here: Beware correlations that make sense in your head but aren’t borne out in practice. Be careful about using the output of a complex process (the game theoretical clash between pitcher and batter on 0-0) to signal something about a hitter. And most of all, maybe be a little more aggressive when you’re pitching to Jacob Stallings: