Grounders in the Age of the Shift

The last factoid I can recall off the top of my head is that there were about three times as many infield shifts in 2013 as there were in 2011. And, in 2014, there have only been more shifts still. The shift, of course, has existed in some form for decades, but I don’t need to overwhelm you with a bunch of specific numbers — it’s common knowledge, at this point, that defensive shifts are in. More teams are doing it than ever, and more teams are doing it more than ever. It’s a part of the game, and it’s gotten to the point at which a shifted alignment isn’t even thought unusual. When the Astros got mad at Jed Lowrie for bunting that one time, part of my defense for Lowrie was that the Astros shifted him, so he should be permitted to use strategy back. Yet the more I thought about it, was shifting a strategic ploy for the Astros, or was it just the Astros playing 21st-century baseball?

But, to cut right to the point, I want to show you a couple graphs. The data comes from Baseball-Reference, and while they don’t split their fields in even thirds, the Play Index does allow one to select balls pulled, balls hit up the middle, and balls hit the other way. I’m showing data only from 2011 onward, because it appears that something changed between 2010 and 2011 that had more to do with the record-keepers than the game itself. Anyway let’s just get to the images.


Groundballs. Groundballs overall, and not just groundballs hit with a shift on. So this is an indirect look, but we know there have been way, way more shifts in 2014 than there were in 2011, so if there’s a signal, it ought to show up. Four years ago, grounders went for hits 23.7% of the time. This year, they’ve gone for hits 24.2% of the time. That’s more of the time! Pulled grounders have been less successful, but there have been more hits up the middle. It’s curious, to put it one way.

But we can easily go a little deeper. Righties are getting shifted now, too, but righties don’t get shifted nearly as often as lefties, so why don’t we look at the same graph, except only for left-handed batsmen?


Overall grounder success has remained unchanged. Batting average on pulled grounders has dropped from 2011’s .220 to 2014’s .186. Yet, up the middle, the average has increased each year. The other way, the average has increased each year. Based on this, the shifts have been working, in that they’ve cut down on hits to the most frequently-populated side, but then that’s been negated by more grounders finding space elsewhere. While, again, this is only an indirect glance, if shifts are way up this year, they haven’t made grounders less successful league-wide.

There’s not much evidence that hitters are getting better at going the other way. In 2011, 7.6% of left-handed grounders were hit to the opposite field. That climbed to 8.1% in 2012, but there it’s remained, and that’s a difference of just one grounder per 200. Fairly trivial. We’re not seeing hitters survive by aiming toward left — we’re seeing them survive because there are still holes. It was already hard to get a hit on a pulled grounder, and adding a defender can make only so much of a difference. And a shift opens up other areas, and just because those areas don’t see that many grounders doesn’t mean the abandoned area won’t lead to more hits. There’s no reason to believe the traditional alignment is the optimal alignment, but today’s alignments don’t seem to be doing all that much better.

As you know, it’s complicated. Some teams shift differently from others. Hitters are aware of the shifts before they’re thrown pitches. Shifts aren’t totally just about scooping up grounders, as there are also certain line drives that can be defended against. Shifts can change a hitter’s approach. Shifted defenders might still be getting used to playing in somewhat unfamiliar spots, which is the kind of thing you’d expect to improve. Shifting, overall, is a work in progress, as it’s still considered sufficiently novel that it gets remarked on during broadcasts. As Jeff Luhnow has said before, it’s not like today’s shifts look identical to the future’s shifts. More and more will be known, and more and more will be taken into consideration.

But here’s maybe the simplest way to put things: there’s been a dramatic trend in baseball, toward a far greater rate of infield shifts. There hasn’t yet been any corresponding dramatic statistical trend. Lefty groundball batting averages with the bases empty:

2011: .220
2012: .220
2013: .227
2014: .222

It seems to me, shifting is obvious. It seems to me, shifting should’ve gotten popular ages ago. It seems to me, the numbers don’t indicate what I’d expect. I can’t explain it, I don’t think, but I can sure point to it. I don’t know why these are the numbers, but I know damn well the numbers are interesting.

Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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9 years ago

Mike Fast posted this on twitter the other day:

“Do some rough arithmetic and see how often shifts would need to happen before you could detect it in BABIP…think like a physicist–not required to know exact number. Guess. Is it .100? .050?.010? And what pct of BIP involve grounders against a shifted infield? Form those two numbers can get BABIP effect.

9 years ago
Reply to  Mookie

I’m confused about what .100, .050, and .010 are. Is that the percentage of time a shift is employed. Or is it a threshold batting average difference between shift and non-shift?