One of the first things Rob Manfred did after becoming MLB commissioner was talk about his idea of limiting or outright banning the shift. The shift has only become increasingly popular! Here is one proxy measure, courtesy of our own leaderboards. This shows the percentage of time there was some kind of shifted alignment in the field when a batted ball was hit in play:

Defenders move around all the time. Defenders move around more than ever. Different places categorize different alignments differently, and it’s not clear where you draw the line between shift and no shift, but the exact definition doesn’t really matter. Shifts are way up, compared to ten years ago. Shifts are way up, compared to five years ago. It’s impossible to watch baseball and not notice, unless you’ve only started watching baseball very recently.

Back then, killing the shift was only an idea. Ideas, for the most part, are harmless. There’s nothing wrong with a thought exercise. But now this is all back in the news. I’ll excerpt a section from an article just written by Jayson Stark:

The commissioner has been contemplating “eliminating shifts” since the week he took the job back in 2015. And now, we’re hearing, support for that idea is building. At last month’s owners meetings, baseball’s competition committee gave the commissioner “strong” backing to try to “put something in place” to limit shifts, according to sources who spoke directly with members of the committee. So next up, it’s time to run this – and more – past the players’ union.

For now, we’re still in the idea phase. No rules have been changed; no left-handed pull hitters have popped any corks. Yet not only has this idea not gone away — it seems to be gathering momentum. Many of us, I think, are beginning to assume we’ll see a pitch clock. Perhaps it’s inevitable we’ll see changes here, too. Maybe in time for 2019! Probably not in time for 2019, but sometimes these things move with haste.

The actual rule-writing would be complex. There would have to be definitions, where no official definitions presently exist. Baseball’s rule book hardly says anything about where the defenders are supposed to defend. It seems likely a new rule would require two infielders on either side of second base. But, when does an infielder become an infielder? Could a defensive team move an outfielder into the shallow outfield grass? Could teams be allowed a certain small number of over-shifts per game, to be deployed strategically? Ideas are always simple until they’re not. Anything here would have to be careful.

In general, I appreciate Manfred’s open-mindedness. I appreciate that he wants to nip things in the bud, before they become problems. It ought to be a good thing for a major sports league to have a proactive commissioner, as opposed to a reactive sort. Other leagues make meaningful changes with some frequency. Baseball needn’t be any different. We’ve gotten used to replay review, as you’ve noticed. We’ve seen a new collision rule. We’ve seen a new slide rule. It’s good to be willing to be creative. Baseball isn’t perfect, and it’ll be pulled in some weird directions, and Manfred is to make sure the game remains entertaining and familiar. I like that the commissioner talks about this stuff. I like that he’s thinking.

I’m just not sold on the shifts idea. Maybe I’m just not seeing the right evidence. And I know that the shift has come on quickly. The league, though, wants to increase action. I’m not sure the shift has decreased action, and there’s even the chance this could backfire.

The shift has exploded as a tendency within the past decade. Which makes sense, after all — this is the information era. Looking at the numbers, we could try to get super detailed, but it’s good to stay simple if you can. In the following plot, you see overall league batting average on balls in play over the past ten years. I’ve also included batting average on grounders alone.

The league BABIP has remained mostly flat. The league average on grounders has remained mostly flat. It’s true that it’s become harder to find hits on the ground to the pull side. It’s also become easier to find hits on the ground elsewhere. And just because BABIP is binary, let’s get somewhat more complicated — here’s league-average wOBA on non-homers hit into fair territory:

Things are…fine. More or less unchanged, through this lens. Now, it’s important to understand we don’t have the counterfactual. Maybe without so many shifts, the numbers would’ve gone *up*. Teams all have a lot of information, and given that teams shift more than ever, they must think it’s doing something. Intuitively, it feels like it should be doing something. It’s weird we haven’t seen bigger changes. But the numbers are what the numbers are. For as much as we’ve seen an explosion of shifts, they haven’t been swallowing up balls in play. The hits are still out there, as long as you make contact.

Individual hitters have been hurt, sure. Certain pull-minded lefties have arguably lost dozens of hits. So, in recent years, have certain pull-minded righties. Eliminating shifts could make things better for those guys. But baseball is a zero-sum game, and if you work to improve conditions for one set, you’re hurting some number of others. What about the other kinds of hitters? What about the pitchers facing the hitters? What right does baseball have to prioritize the Kyle Seagers of the world?

A big part of the thinking has to do with the mindset. That is, there’s a psychology at play when a hitter sees a shift. So the thinking goes, when a modern hitter sees three or four infielders on one side, that hitter decides to try to hit the ball over everybody. There’s concern all the shifting has focused attention on higher launch angles. The theory then suggests that high-launch-angle, uppercut swings lead to more strikeouts. Now, for one thing, launch-angle hitters don’t necessarily always strike out more often. Daniel Murphy seldom strikes out. Justin Turner seldom strikes out. And for another thing, think about what would actually be happening under a new rule. More room would open up on the pull side.

A greater number of pull-side grounders would sneak through for hits. The idea is that this would incentivize grounders and contact. But do you know who hits the most pull-side grounders? Fly-ball hitters. Or, if you prefer, launch-angle hitters. Here’s a simple scatterplot for the past three years. On the y-axis, overall ground-ball rate. On the x-axis, the rate of grounders hit to the pull side.

Pulling or spraying mostly comes down to an individual’s swing. The idea of the rule would be to move defenders from the pull side to the spray side. It seems like that would actually disincentivize trying to hit the ball the other way. By incentivizing pulled grounders, you also effectively incentivize pulled air balls, and just air balls in general. If baseball believes that trying to hit the ball in the air goes hand-in-hand with swinging and missing, it feels like this would only work against them.

Of course, we can’t know all of the actual consequences. Which, as it happens, is one of the dangers. Eliminating shifts would increase the importance of infielder range. Maybe teams would look for rangier infielders. Maybe those more athletic infielders would also be more contact-oriented hitters. I don’t know. There’s a lot. There’s a lot I can’t even imagine.

But if baseball is concerned about action, or pacing, I don’t know what killing the shift would accomplish. Some events would play out differently, yes. But it’s not like fly balls are out of control. Compared to a decade ago, league-wide ground-ball rate is down exactly one-tenth of one percentage point. It’s basically hovered between 43 – 45%. Eliminating the shift could well incentivize more fly balls. If baseball’s worried about action, I don’t think the issue is the shift. I don’t think the issue is the hitters. The issue is the pitchers.

The big trend in baseball has been the rise of the strikeout. Balls in play are less frequent than ever. And, over the past decade, the average fastball has gotten faster by a tick and a half. The average slider has gotten faster by about a tick and a half. The average curveball has gotten faster by more than two ticks. And the rate of sinkers has dropped five percentage points, with breaking balls making up the difference. The run-prevention side already has the information advantage. And the run-prevention side also has the stuff advantage. Every team now has a number of guys who can reach the high-90s, and some of those guys also have wicked secondary pitches. Sometimes those secondary pitches behave like primary pitches! Pitchers are throwing just incredible pitches, and they’re all gunning for strikeouts. Hitters have done an admirable job of trying to adapt, but there’s only so much time hitters have to react to a thrown baseball. That amount of time continues to shrink.

Hitting is hard. Hitting has become harder than it’s ever been. Guys who pitch to contact are going away. The starting pitcher is going away. Now, even at this level, hitters can get used to the stuff. There’s still enough offense in the big leagues. And younger hitters are going to be coming up, guys who’ve seen great velocity, guys who’ve seen defensive shifts. Some of them will have learned to hit the other way. It’s always a push and a pull. As things stand right now, I don’t think Major League Baseball needs to adjust the rule book. Not the part about the defense, anyway. And if baseball does have an appetite to change the game’s results, I think the sport would be better served by either lowering the mound, or moving it back. It’s the pitchers who are causing the strikeouts. It’s the hitters who just try to survive.