Romance of the Four Pitchers

Blind love for the four man rotation

Romance of the Four Pitchers

For a variety of reasons, I’ve been reading the April 5, 1993 issue of Sports Illustrated.

There are a bunch of really interesting subjects that come up in this magazine. However, the one that really surprised me was this utterly idealistic article pining for the days of the four man rotation:

The argument at the core of it is that baseball was worse off because the days of the four man rotation were over. Or, as author Tim Kurkjian put it:

There’s a lot to dig into here, and I’m planning on creating content that will go far beyond this blog post. However, I found that 37.3% number interesting, especially since we can easily check up on it through Baseball Reference.

The trick is to find the “league splits” screen for the season you want to look at. That’s where all the really fun statistical information is — the stuff that lets you know if the old writers are pulling your leg or not.

If you scroll down on just about any season, you can find statistics dividing up pitcher starts by days of rest. Here they are for games started in 1993, for example:

It might surprise you to see one pitcher with a start with 0 days rest. This was rookie pitcher Mike Mohler of the Oakland Athletics.

Mohler struck out Thomas Howard in the 8th inning of the game against Cleveland on July 6, after whic he hit Carlos Baerga with a pitch. He was lifted in favor of Goose Gossage after throwing a grand total of 6 pitches.

Mohler then started the July 7 game against the Indians, going 3 1/3 innings and giving up only 2 hits and 0 runs. Oakland won, but Mohler didn’t get credit because he didn’t go 5 innings.

In other words, you can’t necessarily say that pitchers were somehow “weak” in 1993. On the contrary: sometimes pitchers were asked to perform difficult tasks because of roster situations.

Now, compare those stats with 1973:

You can see that there were more starts on 3 days of rest in 1973 than in 1993, sure. But you can also see that batters fared much better against pitchers on 3 days of rest than those on 4 days of rest. This flatly contradicts a number of claims made in the article.

In 1993, pitchers did a little bit better with 3 days of rest. But, then again, this is likely because pitching on 3 days of rest was the exception, not the rule. If you were forced to do it, you’d probably be more likely to ask your ace to take on an extra start, not to give a start to your number 5 guy on short rest.

Or, in other words, pitchers actually do need rest.

For fun, here are the stats for 1953:

And here they are for 1933:

And, finally, here is 1913:

Now, when you look closely at these stats, you’ll see that it has never been the case that every single team has run a 4 man rotation. In fact, a significant number of pitcher starts from every season in baseball history came from pitchers who had not pitched in a major league game for 6 days or more.

This doesn’t mean that teams didn’t use a 4 man rotation. What it does mean, however, is that the rotation of the 1971 Baltimore Orioles was the exception, not the rule.