When I was in middle school, my favorite joke was: “Three guys walk into a bar. The fourth one ducks.” It scored well with my friends. I enjoyed the twist, the simplicity and the imagery. Unlike most of the other things I liked when I was in middle school, I’m not ashamed of this one today. My tastes, though, have changed. If I had to pick my favorite joke now, for example, I’d say it is one of two things. It’s either any joke told by John Mulaney, or it’s the fact that my Firefox spellcheck suggests replacing “Altuve” with “altitude.” It’s funny because it’s true.

Jose Altuve is remarkable simply because he’s a major leaguer. There aren’t a whole lot of those, and there are fewer still with Altuve’s promise. But among major leaguers, Altuve isn’t outstanding. He’s fine — and he’s very young — but people figure he’s better than he is because of the team he plays for. He looks better in context. If Altuve is widely known, it’s only in part because of his talent; more, it’s because he’s so little. The most notable thing about Altuve is the whole major-league thing. The second-most notable part about Altuve is that, for a major leaguer, he’s short. For a non-major-leaguer adult, he’s short.

Officially, Altuve measures 65 inches. Unofficially, he doesn’t, but we don’t have those measurements so we have to use what we’re given. No player in baseball has measured fewer than 65 inches since 1956. Since then, five players have come in at 65 on the nose: Altuve, Freddie Patek, Al Montreuil, Albie Pearson and Fritz Brickell. Brickell and Montreuil barely played, which puts Altuve in even more limited company. By official measurements, he stands an inch shorter than David Eckstein, and I feel like I have to repeat that Altuve, in reality, is not that many inches tall. In fact, he might be the shortest player in decades.

That means a few things. Obviously, it hasn’t meant enough to keep Altuve from the majors, so we know he possesses exceptional ability. The majors look for great talents, so despite the height, Altuve must be able to hit for contact or power or both and he must be able to play a position. He seldom swings and misses, he’s got 14 career dingers and he can cut it at second base. So far in his career, he’s been worth about three wins above replacement, and he turns 24 next May. The Astros like Altuve enough to have given him a four-year contract.

So where does height come into play? Where is it a direct factor? The answer is the strike zone, because, at least in theory, the zone’s dimensions depend on each batter’s physical specifications. Altuve’s zone, therefore, ought to be particularly small. This is particularly fascinating to me. I’ve written about it before, but not for more than a year, so I thought I’d re-visit. I’d like to take a look at Jose Altuve’s called strike zone.

PITCHf/x operators assign batter-specific strike-zone borders every game. Obviously, nothing changes horizontally, but there are different vertical edges depending on each hitter. This season, the average lower edge of Altuve’s zone has been about 1.3 feet off the ground. The average upper edge of Altuve’s zone has been about 2.8 feet off the ground. These are low dimensions, as you might expect.

I thought I’d compare Altuve to Alex Rios, because the data show Rios appears to have one of the tallest assigned PITCHf/x strike zones. This season, the average lower edge of Rios’ zone has been about 1.8 feet off the ground. The average upper edge of Rios’ zone has been about 4 feet off the ground. That’s an upper-edge difference of more than a foot. So how have things actually been called? Here are Altuve’s and Rios’ called strikes for 2013, with approximate zone boxes included:

For Rios, there’s not much near the upper edge, and there are some strikes below the lower edge. For Altuve, the zone hasn’t dropped low, but we see an awful lot of strikes above the upper edge. Altuve is short, but umpires have called his zone as if he isn’t as short as he actually is. There’s a difference between the Rios zone and the Altuve zone, but just eye-balling it, the difference doesn’t seem big enough.

For fun, here are 2013’s five highest called strikes with Jose Altuve at the plate, in descending order:

5

4

3

2

1

The league average is that about 7% of pitches out of the umpire strike zone are called strikes. This is going off the zone as it’s actually called, as opposed to the zone in the rulebook. Here’s where Altuve has checked in since he debuted in the bigs:

2011: 12%

12% 2012: 12%

12% 2013: 12%

Altuve has more balls called strikes, and there’s no sign of any umpire adjustment. Altuve also has a slightly below-average rate of pitches in the zone that are called balls. Umpires are calling Altuve’s zone bigger than it ought to be, and it’s pretty much entirely because of the high strike. To most hitters, a pitch at the letters is an automatic ball. With Altuve, there’s doubt.

This is probably what we ought to expect. In theory, the zone changes for every batter. In reality, umpires are accustomed to calling a certain strike zone. They have a mental idea of what strikes look like, so it’s tricky to take into account batters of unusual heights. Ask any umpire and he’ll tell you the zone gets smaller with a shorter batter, but it’ll be hard to make sure it gets short enough, because the idea of the zone is embedded. The reality of the short hitter is new information. It presumably works the same at both ends. Smaller batters will have more high strikes. Taller batters will have fewer high strikes and more low strikes. It’s just hard to appropriately customize a strike zone to each hitter on the fly, because humans have limitations and pitches go fast. When Altuve walks up, umpires know he’s the shortest player in baseball. When a pitch is thrown to Altuve and taken, the umpire quickly compares it to pitches he’s seen in the past, which were thrown to taller hitters.

So, in a sense, Altuve is at a disadvantage. His actual strike zone takes up a greater amount of his body. It also just isn’t the ordinary strike zone — it’s shifted up. But then, this didn’t become the case simply upon his promotion to the majors. Altuve, I’m guessing, has always been little, which means he’s always had to deal with this. Umpires are human, and the umpires calling balls and strikes now are theoretically the world’s best. Altuve has made the majors despite how his zone is called, and this should be more or less the zone he’s used to. He’ll still have disagreements with pitches at the extremes, but Altuve must understand that his zone isn’t as small as the rulebook says. That’s unlikely to change.

And? In his career, Altuve has put 137 pitches above his rulebook zone in play. Within that sample, he’s posted a .328 BABIP. That’s better, even, than his overall BABIP. Jose Altuve is a regular in the major leagues, and in order to pull that off, he’s had to overcome considerable disadvantages. In the field, he can play a bigger man’s position. At the plate, he can make do with a bigger man’s strike zone. No, Altuve isn’t great, and he might never be, but that’s hardly the point. The point is that you know who Jose Altuve is. And, really, that’s the most amazing thing.