The Brewers' Outfield Defense Takes an Unusual Shape. Why?

[Matthew Trueblood]

New rules that took effect last season forced MLB teams to align their infields in relatively similar ways. The outfield remains an ungoverned frontier, though--or at least, the field itself confines teams' choices, rather than the rule book.

Image courtesy of © Joe Puetz-USA TODAY Sports

How does the shape of an outfield array affect the way the players who comprise it play? What determines where outfielders set up, and how they align themselves relative to one another? Do teams need to look for different essential skills in their outfielders based on the way they prefer to (or have to) set up their defenses?

It's not something we tend to think about much, because defense in baseball is more about roughly equitable coverage of a large field than it is about funneling an offense toward a specific area or defending against favored positions. By the reckoning of most baseball people, hitters have relatively little control over where any given batted ball goes, so defensive alignments are about managing probability and situation. The psychological aspect--the anticipation and preemptive adjustments, and certainly most elements of surprise or disguise--that heavily influences defense in football, basketball, and soccer is largely absent in our game.

Defensive positioning obviously matters a lot, though. That's why the league implemented rules forcing four infielders to stay on the dirt, and to divide themselves more evenly, with at least two players on each side of second base. It also matters in the outfield, and in our data-informed age, the average outfield alignment is changing rapidly. Look no further than the league's average starting depth for center fielders in each year of the Statcast Era to see evidence of this:

• 2015: 311 ft.
• 2016: 316 ft.
• 2017: 318 ft.
• 2018: 318 ft.
• 2019: 322 ft.
• 2020: 323 ft.
• 2021: 322 ft.
• 2022: 322 ft.
• 2023: 323 ft.

It's been a few years since we saw a large jump in this area; the league has come much closer to what everyone understands to be the optimal depth. Still, there's a persistent trend. Outfields are playing ever deeper, to counteract hitters who are hitting more, harder line drives and fly balls. 

Outfielders are constrained in where they can play not by the rules (they're even welcome to come in and form five-man infields, if a team is sufficiently convinced of the need for an old-fashioned shift), but by the very walls behind them, and by the limits of their own and their teammates' talent. Famously, center fielders of yore (and ones as recent as Andruw Jones and Jim Edmonds) took pride in playing exceptionally shallow, where they could take away would-be bloop singles more often. They felt they could always go back and catch deep flies, using their singular speed and ball-tracking ability.

The reality of the situation was probably always that they were giving up more value than they were saving, allowing an extra double or triple for every one or two singles they took away. Now, in a league much more densely populated with guys who can hit for power, there's no question of the folly of playing shallow, especially as we all gather more data about just how much harder it is to go back on the ball than to come in on it.

By and large, then, outfielders play as deep as they can, with the limits being:

1. The dimensions of the park;
2. The range of their fellow outfielders; and
3. The risk of a single through those newly tightened infields, and the need to come in and collect them quickly, to prevent runners from taking extra bases.

The first factor is the most important. Teams whose home parks have very shallow corners and very deep center fields (think Yankee Stadium, Minute Maid Park, Angel Stadium) tend to play outfields that look more like a triangle (albeit a flat one). Teams with deeper-than-average corners and cozy power alleys and center fields, by contrast, play something closer to a straight line or flat arc across the grassy expanse. The best three examples in baseball, perhaps, are Busch Stadium, Wrigley Field, and Miller Park. And hey, look at this:

The Brewers use, perhaps, the flattest outfield shape in MLB. That's not a coincidence. It's a factor of where they play, but also of the skill sets of their players at those positions. Christian Yelich plays a deep left field, not only because the left-field foul pole in Milwaukee is 342 feet from home plate, but because neither he nor the team wants him going back on the ball any more than is absolutely necessary. Meanwhile, Jackson Chourio is playing most of the time in right field for the Crew, and he's still fairly inexperienced there, so erring on the side of playing deep is wise. It's already paid off a couple of times for the team, as Chourio has taken imperfect routes on deep balls but still gotten under the ball in time.

Just so, the fact that the Crew's center fielders play shallower than most is about more than the fairly tight dimensions across the middle of the diamond at home. It's also because both Yelich and Chourio (or whoever occupies the corners) have to cheat a bit toward those deep corners, especially with runners on. The center fielder has more responsibility for the gaps in Milwaukee than elsewhere.

For that reason, there's one more interesting idiosyncrasy of the Brewers' outfield alignment: they change it more than most based on the handedness of opposing hitters. Here's the Royals' defensive alignment heat map for this young season, as a baseline to which to compare.

Now, here's the Cubs, another team whose outfield alignment is flattened and affected by the parks in which they play. This is what we'd expect to see if only the park were shaping how the Brewers position their outfielders.

Here, though, is the actual way the Brewers set themselves. (All of these are for road games only, which is the best way we can try to strip out the distortionary effects of home parks.)

Pat Murphy, Andrew Fox, and the rest of the Crew's defensive positioning decision-makers clearly want their center fielder (most often Sal Frelick) shaded more heavily toward the direction in which the opponent is likely to hit the ball than most teams do. They're trying to facilitate cutting off a ball toward the corner or the gap toward which the ball is more likely to be hit, by having Frelick (or Blake Perkins, or whomever they put out there that day) cheat toward the corner under greater threat, so that that corner guy can cheat that way by a few steps, too. It pulls the off corner man more toward center than most teams play them, in case a ball does get hit the "wrong" way, but the team is trying to manage probabilities and maximize their chances to make good plays. 

So far, it's hard to argue with their choices. Only the Red Sox (5) have more Defensive Runs Saved (DRS) based on outfield positioning than the Brewers (3) do, according to Sports Info Solutions. They've benefited from having some very gifted athletes and skilled defenders in the outfield, but they've also had to weather the difficulties of having a rookie starting in one spot; a player who took most of his spring reps on the infield at another; and an aging veteran with a poor defensive reputation at the third. That they still catch the ball well and have saved runs (despite a net 0 DRS from their outfielders based on range and arm) out there so far is a testament to the wisdom of this approach. It's another small way in which the Crew are staying ahead of the curve, sometimes under difficult circumstances.

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[Playing Catch]

Good stuff.