Improving Pitching Efficiency Leads to Fewer Pitches

Let’s start with a riddle: Team A and Team B have both played 98 games this season. Due to the vagaries of extra innings and unplayed bottoms of ninths, Team A’s pitchers have thrown four more innings than Team B’s pitchers. However, Team B’s pitchers have faced 259 more batters than Team A. How is this possible?

OK, yeah, so this was actually a pretty easy riddle. The answer is that Team B’s pitchers stink, while Team A’s pitchers are very good. Team A gets a higher percentage of batters out, which means that it faces fewer batters per inning. Let’s put some names and numbers to our hypothetical, shall we? Allow me to introduce you to the Mariners and the White Sox.

The Mariners have better pitchers and a better defense behind them. Consequently, the White Sox have allowed a whopping 130 more runs. But take a look at the last row of that table. The White Sox have thrown the most pitches in baseball, while the Mariners have thrown the second fewest. Having good pitching and good defense has allowed them to throw 1,477 fewer pitches than the South Siders. The average team throws 146 pitches per game, so we’re talking about 10 entire games’ worth of pitches. Ten games! That is a huge number, and these teams still have 64 games left to go.

There are virtuous and vicious cycles goosing these numbers. If you’re the Mariners and Logan Gilbert is mowing down the other team, he’ll be able to go six or seven innings, which means that you’ll only need to bring in your top two bullpen arms to close out the game. Since they’re great too, they’re also likely to throw fewer pitches. That leaves your bullpen better rested, which improves its chances of pitching better in the future, which again means fewer pitches per inning. For a bad team, the opposite happens. Your starter struggles and only makes it four innings, so you have to go much deeper into your bullpen and use your worst arms more often, all of which means throwing more pitches. When your starter struggles again tomorrow, your relievers are tired, which makes them pitch worse, which means more pitches — and maybe even more injuries, so you have to bring somebody even worse up from Triple-A — and the cycle continues.

Regardless of how you end up there, these differences are so large that I’m genuinely having trouble wrapping my head around them. Here’s what a full season looks like. In 2023, the A’s threw 25,303 pitches. That was nearly 10 games’ worth of pitches more than the average team, and nearly 17 more than the Rays, who threw the fewest pitches. I usually try to do more analysis in my articles than throwing up my hands and saying, “Holy cow, what a big number!” But in this case, I think that’s actually the correct takeaway. These numbers are enormous. The regular season is a slog and a war of attrition for every pitching staff, but the worse you are, the greater the slog. I know that teams often think about maximizing this effect over the course of a series: Make them throw a lot of pitches in the first game so that they have to bring in their worst relievers in the second and third games. But now we’re talking about a whole season. I’m not sure how to analyze it just yet, but this is a huge effect that I just plain haven’t heard anyone talk about before.

As you’ve probably realized by now, this pattern works in reverse when it comes to batting. Teams that get on base more and avoid running into outs on the bases earn more plate appearances per inning. The Dodgers are leading baseball in PAs right now. Last year, they had 367 more plate appearances — 70% of the way to a qualified player season — than the A’s. Having more PAs to go around also means that your batters are seeing more pitches. Depending on your playing time philosophy, it might mean that your backups get to hit more often, which might keep them sharper and give your starters more rest, which could once again help your team hit better overall.

Here’s a fun thought experiment: In 2022, the Yankees had 103.6 more plate appearances than the MLB average. What if Aaron Judge had been on the A’s, who made 205.4 fewer PAs than the average? Obviously, having Judge would have made the A’s better, likely earning them a bunch more PAs, but even factoring that in, it could have easily cost him upward of 25 PAs. Might that have been enough to keep him from breaking the AL home run record?

As you can probably tell, I haven’t really made up my mind about how to think about this effect. I started pulling the numbers without any idea how big the effect would be, and right now I’m pretty shocked, so I’m going to stop here and give myself some time to think about what it means. However, before I go, I want to leave you with one final question.

In the first paragraph of this article, I mentioned that we needed to account for extra innings. I also mentioned that we needed to account for games that end after the top of the ninth because the home team is ahead. That’s quite a mouthful, and as I was writing that sentence, I realized that there’s no term for a game that ends that way, but there really should be. My best suggestion so far is a Bottomless Ninth. When I put the question to my colleagues, Leo Morgenstern stuck with the bottomless theme, suggesting that we call it a Winnie the Pooh. (Jon Becker chimed in with the Daffy Duck. Why are so many animals wearing shirts without pants?) Readers of FanGraphs, the time has come for you to contribute your brilliant ideas. What should we call a ninth inning that only has a top half? Please offer your suggestions in the comments or on social media. Together we can fix this gaping hole in the baseball lexicon.