The effect of the three-batter minimum is being underrated

For the first three years of the designated hitter, there wasn’t necessarily a belief that it would stick, and some managers even opted out at the beginning out of protest. It was instituted as a three-year trial, remember, and not a permanent change to the game, and it wasn’t used in inter-league World Series games at American League parks until 1976.

The thinking was that once the fad wore off, it wouldn’t need to be added to the Fall Classic because it would be gone by then. But rule changes, as we now know, are quite difficult to unilaterally reverse, especially ones that alter a team’s operations for good.

Not that this change will be on the order of magnitude of the DH, but the new three-batter minimum will have a significant effect on games. Maybe I’m a fuddy-duddy purist, and I don’t consider myself one, but I think it’s important to keep the DH example in mind, that there was even an idea of a “roll-out” period where the league could determine if it works. For now, MLB is using the Atlantic League as the testing ground.

There’s no really telling how this might, in the short term, swing the fates of certain players and teams in favor (and disfavor). There’s at least some thinking that the effect will be minimal:

Mike Petriello wrote an article to that effect at MLB.com, stating that it wouldn’t change too much, and that it would fix the issue of pitching changes taking too much time. And while short relief appearances are becoming more rare, they are still incredibly common:

We’ve essentially wound the clock back to 2010 as far as short appearances go. This rule would bring that number to not exactly 0, because pitchers will be able to end an inning with fewer than three batters, but it’ll be back to, say, post-World War II, which is a quite different era!

It’s decreasing, as we see, but there is still a non-trivial amount. Let’s think of it in terms of wins, which is the real currency of pitching appearances. Most of these appearances to get a match-up are naturally in higher leveraged times, so it’s telling what the distribution of WPA is for these appearances, in this case where the pitcher isn’t trying to end the game (most cases where there are fewer than three batters faced in the ninth, the game ends):

When you include the ninth inning as well, it’s even more stark: 23 appearances had a WPA above .250, and 34 had an average Leverage Index above 5. Yet there were still 300 short appearances before the 9th inning, and about half of them affect the game by about 1/10 of a win.

Combined, that’s a total of 35 wins, and that’s just the ones that will mostly be removed. If there are thousands and thousands of combinations of standings combinations, and win combinations, 35 wins spread around will completely shuffle the standings in a way we can’t even expect, and it could cause teams to over-or-under-perform their Pythagorean record if their bullpen wasn’t suited for longer appearances.

Which teams are prepared is probably going to be the biggest effect of this rule:

The Yankees, for example, have essentially removed the LOOGY from their repertoire, and most of their relievers are platoon-resistant. Yet the Phillies had well over 100 of those instances, and Adam Morgan and Luis Avilan combined for over 50 themselves, along a list of a solid number of relievers:

The LOOGY is dying, yes, but the league is still making a choice to make the Jerry Blevin’s, Andrew Chafin’s, and Oliver Perez’s of the world go extinct. Those didn’t exist in most of baseball, yes, but that wasn’t from an instant rule change! That took decades and happened naturally from the changing landscape of the league, not overnight.

Not to mention, there are more changes down the pipe: caps to pitching changes, roster changes, mound visit changes, possibly mound changes, and a universal DH. If the league had to trial a DH the first time, who’s to say that this change, combined with others, will change the game innumerably overnight?

Will it end the sport? Obviously not. Will people get over it? Of course. But pretending that these changes won’t change things, when we see thousands of appearances like this per year, would be naive, and it would underrate how much a rule change can swing the league, something we should keep in mind as the league swiftly re-writes the rule book.