The Most and Least Team-Friendly Strike Zones

It feels like it’s been a little time since I wrote about the strike zone. As such, it’s time to go back to the well, to a piece I get to write every season. To kick it off, how about a mention of the incredible, improbable Tyler Chatwood? Through a dozen starts, Chatwood is sitting on a sub-4 ERA. And he’s allowed only one unearned run, so, in a way, he’s already paying off. And yet, over 58.1 innings, Chatwood has 53 strikeouts and a genuinely unbelievable 56 walks. He’s running what would stand as one of the very highest walk rates in all of baseball history, and he’s routinely struggled to throw even half of his pitches for strikes. Related to this, the Cubs’ pitching staff has baseball’s highest team walk rate. The White Sox are next. The Indians’ walk rate is the lowest.

The strike zone itself is a funny thing. It is, of course, supposed to change for every hitter, depending on their height or stance, but the zone is fundamental to the game. Everything revolves around the strike zone, and there’s nothing in the rule book that would suggest that one team should get a different zone from another. But we know the team-to-team zones aren’t consistent. We actually sometimes celebrate the pitchers and catchers who can manipulate the zone to their benefit. Teams end up with friendly zones, and teams end up with less friendly zones. The zones can affect strikeouts, the zones can affect walks — the zones can affect records. It’s a part of the game we currently just have to accept.

Accept and acknowledge. Accept and observe! Accept and analyze. With the way the game is played in 2018, it’s a given that all the zones end up being a little bit different. Which teams this year have been happy about their zones? Which teams might have reason to complain? I’ve got a couple tables for you. You can skip all the words if you want. It’s only the numbers that matter.

I like to analyze the zone in terms of strikes above or below average. One strike is worth only about a sixth of a run, but then, because you’re familiar with math, you see how that can add up quickly. I’ve gotten all of my information from Baseball Savant. The idea is to find the difference, for every team, between actual strikes and expected strikes. I calculated the difference for every team’s pitchers, and I calculated the difference for every team’s hitters. For purposes of the table below, I flipped the hitting numbers around, so that, in all columns, a positive number is good for the team, and a negative number is bad. The “Total” column is self-explanatory, and the remaining columns just show the various ranks. The table below is sortable.

So that you know how to read this: Compared to the average, the Indians’ zone has been team-friendly by about 91 strikes. The White Sox’ zone has been team-unfriendly by about 134 strikes. These numbers are only estimates, so you should take them with a grain of salt, but this is capturing plenty of signal along with the noise.

According to these numbers, combining pitching and hitting, the most team-friendly zones have belonged to the Indians, Rockies, Diamondbacks, Mariners, and Angels. At the other end, we find the White Sox, Reds, Pirates, Royals, and Brewers. The White Sox are quite a ways out there, and then the Reds are also pretty well separated from 28th place. By no means does this table show why the Indians have been pretty good while the White Sox have been pretty bad, but this is a part of the bigger picture. And it’s illuminating to look at the pitching and batting columns separately.

The pitching column will be related to pitch-framing effectiveness. The better the framer a team has, the fewer strikes that team will give away. But it’s also not all about pitch-framing — you also have to keep the pitchers themselves in mind, because some pitchers are able to locate a hell of a lot better than others, and no one can frame a wild pitcher very well. Thinking about the Cubs for a moment, it’s hard to imagine a worse combination than Tyler Chatwood and Willson Contreras. Chatwood is a very wild pitcher, and Contreras rates as a below-average framer. Put them together and the zone is almost destined to shrink.

From the mound, the Diamondbacks have pitched with easily the friendliest zone. The Dodgers are a distant second, with the Indians a close third. The White Sox bring up the rear, followed by the Royals and Pirates. The Pirates’ placement interests me, because, in the recent past, Francisco Cervelli rated as a quality framer. Since the start of 2017, he’s lost that skill, which is somewhat perplexing. At least he’s figured out how to hit for big power.

The batting column is a little noisier. It’s always harder to explain the variations here. Some of it is presumably a reflection of hitter skill. Some of it is randomness, and some of it is opponent pitch-framing. The A’s, Rays, and Rockies have hit with the friendliest zones, relatively speaking. The Yankees are at the bottom, followed by the Marlins and Diamondbacks. Note that, in the pitching column, the standard deviation is 52 strikes. In the batting column, it’s just 30 strikes. The former is more meaningful, even though the latter also matters.

As another consideration, I calculated all the same numbers for 2017. In this sortable table, then, you can see how all the teams’ ranks have changed year to year. A positive change is good. For example, the Rockies have moved up 21 spots.

Two years ago, the Rockies played with the 23rd-ranked zone. Now they’re in second, meaning they’ve jumped by 21 places. Just in the pitching column, they’ve jumped by 25 places, which is awfully dramatic. If you look at the bottom, you see the Cubs, whose zone-friendliness has fallen by 16 places. It’s probably not a total coincidence that Chatwood went from Denver to Chicago during the offseason. Anyway, another big change has happened with the Mariners, whose pitching zone has improved by 19 places. They’ve given some of that back on the hitting side, but the Mariners will take whatever they can get. And as for the rest, you’re free to peruse to your liking. This is only a small part of baseball here being analyzed, and the wins and losses are about so much more than just this, but still, it’s worth being reminded every single year that every team plays with slightly different rules. It’s an open question as to whether that makes the sport better or worse.