The Best Four-Seam Fastball Hitters of 2021

Hitting is a multi-faceted skill. The best batters don’t share the same cookie cutter profiles; Max Muncy and Shohei Ohtani, despite producing similar overall value at the plate, get to it in very different ways. You can wait pitchers out or attack their mistakes, feast on bad pitches or foul off their best offerings. But if you want to know who looks like the best hitter, there’s an easy metric: who does the best against fastballs?

There’s something viscerally satisfying about obliterating a good four-seam fastball. The best curveballs to hit look easy to hit; they’re lollipops that hang over the middle of the plate, and by definition they’re slow. Even a fastball that misses location has that “fast” going for it. That’s not to say that they’re harder to hit, or that it’s the best way to think of good hitters, but when it comes to the eye test, fastball hitting is second to none.

So then, who are the best fastball hitters in the game? There’s no one way to answer it, so I thought I’d take a crack at coming up with my own answer. One thing you could do is simply look at our pitch values. Using Pitch Info fastball classifications, here are the best hitters against four-seamers this year:

Hey, great, article over! This was a quick one; you’ll have time to grab a bite to eat or get up and stretch your legs with the time you thought you were devoting to it.

Okay, fine, pitch values aren’t the final word on who hits best. They’re heavily reliant on batted ball results, and those take forever to stabilize. Turning a few seeing-eye singles into outs would have a huge effect on pitch values, though the actual contact quality would be no different. In the long run, on average, they work well. But we’re not looking for the long run, or for average. We’ll need to do better.

I decided to come up with my own way of looking at things. I wanted to capture two factors: avoiding strikes and mashing the ball on contact. To weigh those two things equally, I decided on z-scores. Why? There’s no obvious common unit for the two, but converting them into normalized values lets us combine them. It also handles the fact that player skill varies differently in different places; there’s a lot more variation in barrel rate than, say, hit-by-pitch rate.

To capture strike avoidance, I looked at CSW%, the percentage of the fastballs a batter sees that result in either called or swinging strikes. Swinging strikes are obvious; great fastball hitters don’t windmill through fastballs without putting a charge into them. Called strikes aren’t as clear-cut, but for me, a fearsome hitter letting a hittable pitch pass without going for broke is a negative sign. I want my fastball hitters hitting, not standing at the plate with a bat on their shoulders and letting value go by.

Who fulfills this quality best? I’m glad you asked. Here are the ten hitters with the lowest CSW% on four-seam fastballs, minimum 200 seen:

Well, this group is certainly aggressive. Fearsome hitters aren’t merely the ones offering at the ball, though. They’re the ones whose swings put fear into pitchers. We’ll need another leaderboard.

Let’s also change stats. I could have used something like barrels per swing or barrels per fastball seen, but I wanted a slightly different metric. What’s scary contact? It’s hard, and it’s in the air, but not so high in the air that it’s a pop-up. I decided on a definition that captures those two things: balls hit 100 mph or more and between 10 and 40 degrees. I called them smashes, but don’t take that as gospel; I just wanted a one-word descriptor for this article.

This works out similarly to barrels, and I think it’s true to my goal of finding the most dangerous hitters. I used swings as the denominator; for me, it’s a better reflection of who the best hitter is than using balls in play. If a hitter swings at 100 fastballs and puts only one in play, I don’t care how hard it’s hit; that’s not a hitter I’m truly afraid of. By looking at swings, we can get a truer idea of how likely a player is to do something notable when they take a hack.

By this metric, here are the most fearsome four-seam hitters in the game (minimum 50 swings):

Now we’re talking! These guys mostly fit the mold I’m looking for. If you asked pitchers who they most feared making a mistake against, Buxton would surely be near the top of the list. Tatis and Guerrero obviously deserve spots. Aaron Judge, Kyle Schwarber, Juan Soto, and Miguel Sanó all just missed the top 10 cutoff. Also: Adam Engel! I wouldn’t have expected to see him on there, but he’s having a great season and doing it all against four-seamers.

Next, I converted each metric into z-scores (how many standard deviations away from league average each mark is) and combined them. Without further ado, here are the best fastball hitters by my definition, as well as the constituent z-scores:

Buxton’s smashes per swing are off the charts. You could convince me that he hasn’t played enough to be on the list, but I couldn’t resist showing off such a dynamic result. The rest of the list is a bunch of hitters who I know pummel the ball — and, again, Adam Engel. Hey, what can I say? The man has been up to the challenge this year.

If you wanted to, you could tweak my definitions. Maybe taking a fastball for a strike doesn’t strike you as a problem. Why penalize a hitter for taking a fastball on the corner in a 2–0 count? We don’t have to. We could use whiffs per swing instead. Now letting pitches fly by is less of a dealbreaker than trying and failing.

While we’re at it, let’s replace “smash” rate with barrels per swing. We have this fancy Statcast number; no sense in not using it. Here’s a blended z-score version that uses whiffs per swing and barrels per swing instead of my initial selection:

This is a slightly different group, but still full of some fearsome mashers — and Andy Ibañez. He’s a contact-happy hitter, which I suppose explains some of it, but all I can say is that baseball can be weird. I have no reason to doubt the numbers or anything, but it’s certainly a strange name to see atop the list.

To assuage any Ibañez-related doubts, I decided to combine all four numbers together. Here are the best four-seam fastball hitters, as defined by jamming CSW%, whiffs per swing, barrels per swing, and “smash” rate into one giant blended mess — and what the heck, let’s go 20 deep this time:

Are these the most fearsome fastball hitters in the game? I have no reason to disagree. Every one of these hitters does a lot of things right: they don’t take too many strikes, and when they swing, they get their money’s worth — even Ibañez. And fine, you made it this far in a chart-heavy article. You deserve a treat. Here’s Byron Buxton reducing a ball to its constituent atoms: