The Dodgers Have Played With the Friendliest Strike Zone

There’s a certain asymmetry allowed in the game. Lineups can be arranged in whatever order. Defenses can be shifted however you want. The biggest and most obvious example is how every single home ballpark is unique. Distances are the same from mound to plate, and from base to base, but outfields and fences are completely different, wherever you look. It’s counted among baseball’s various charms, and I can’t recall anyone ever complaining. Every park is a different park, and it’s something we’re pleased to accept.

Yet, in theory, there’s one core component of the game that’s held constant for everybody. In theory, every player and every team is to work with identical strike zones. It would be absurd for the rules to allow the zone to be flexible, beyond considering a hitter’s particular stance. The zone is something fundamental, something necessarily equivalent, and there’s no good reason why any team should stand to benefit. In theory.

In reality, we know better! In reality, we know certain teams get better zones than others. Some of it comes down to randomness. Noise alone could explain certain fluctuations. Yet some of it is also by design. You’re the last people to whom I need to explain the concept of pitch-framing. This isn’t all about framing, but that’s a big part. Anyway, they’ve played almost three months of 2017 regular-season baseball. To this point, the Dodgers have received the friendliest strike zone, by far.

This is a post I probably write once or twice a year. Once somewhere around the middle, and then probably once again around the end. And it’s all based around some very simple math. Using the FanGraphs stats, you can find a team’s actual strike total, and you can also use the information to calculate an approximate expected strikes total. All that’s left is to compare the two. Generally, you see this done for pitchers. You can also do it for hitters, because why *couldn’t* you also do it for hitters, and in this post I’ll show you everything, including the numbers combined.

Before advancing to the data, let me remind you that this is simplistic. I like this analysis because it’s easy to perform, and it’s not perfect, because it’s not granular. The best form of this analysis would look at every single pitch individually. So, everything in here is an estimate, and some numbers are presumably off, but I feel good that there would be a strong relationship between these numbers and the hypothetical superior numbers. So then! Let’s begin with a bar graph. Here’s every team in baseball, along with their extra strikes above or below average. Positive numbers are good for the teams. Negative numbers are not.

Based on my math, the Dodgers have benefited from 237 calls, compared to the average. Their pitchers are at 188 more strikes than expected, and their hitters are at 48 fewer strikes than expected. All I’ve done is add the two up. The team in second is all the way down at 135, meaning the Dodgers are in first by more than 100. In fact, the Dodgers’ lead is exactly the same as the third-place Cubs’ *total.* The Dodgers are ahead of the Indians by 102. The Cubs are ahead of the league average by 102. This is mostly a credit to Yasmani Grandal, but some of the credit also goes to the Dodgers’ pitching staff. Not to mention, the hitters have helped out a little bit.

If you look at the other end, the Phillies are in last, because they might as well be in last place in everything. Among teams in or vaguely around contention, the Rockies, Royals, and Tigers have fared poorly. The Tigers have a recent history of faring poorly in this statistic. But, enough of looking at things overall. Here’s a plot of the hitting and pitching breakdown:

Because it’s unlabeled, it’s not very helpful. And so I’ll embed this table, that I think is supposed to be sortable. All positive numbers are good, and all negative numbers are bad.

The staffs that have worked with the best zones: the Dodgers, Orioles, Braves, Diamondbacks, and Astros. None of those are too surprising, except for maybe the Orioles, but Caleb Joseph has been more defensively good than Welington Castillo has been defensively bad. For the Diamondbacks, getting better in this department was an offseason priority, so it makes sense they are where they are. One might’ve reasonably expected the Twins to look better, but it’s not so easy to work with that pitching staff. It could make any catcher look worse.

Flipping things around, the Tigers have pitched with the cruelest zone. But then the Rockies are second from the bottom, which isn’t what was expected, but Tony Wolters hasn’t been the framer it looked like he was going to be. The Reds, Phillies, and Mariners round out the bottom five, and it’s interesting to see the Mariners there, too, given Mike Zunino’s history as a quality receiver. I’m not here to examine anything in depth. I’m just passing numbers along.

Now, it’s worth noticing that Nationals and Twins *hitters* have fared well, in terms of getting the benefit of the doubt. The same cannot be said of the Braves. The Braves have the largest positive difference between their pitching total and their hitting total. The Tigers have the biggest negative difference. Intuitively, it makes sense that the hitting numbers are more subject to randomness. It hasn’t been conclusively proven that hitter zones are much of a skill. For an idea of significance here, I ran an analysis of the 2016 data, splitting the first and second halves. Between halves, the pitching numbers had an R2 of 0.37. Meanwhile, the hitting numbers had an R2 of 0.10. The hitting numbers are more random, and regress harder, and so if you had to choose one of the two areas to excel, you’d take the pitchers. You already knew that, I imagine, but I’m giving support to your assumption.

That makes these numbers look worse for teams like the Mariners, Rockies, Tigers, and Nationals. Moving forward, their negative pitching numbers are more likely to keep up than their positive hitting numbers. And then, this looks good for, say, the Braves, Orioles, and Diamondbacks, for the same but opposite reason. Their hitters have been penalized, but that shouldn’t happen so much anymore. And their pitchers will probably keep the benefit of the doubt.

It’s a part of the game today that the actual zone isn’t equal for every player and every team. Perhaps it’s not always going to be that way. An automated strike zone would reduce all this to pretty much nothing. We’re not there yet, for better or for worse.