How does Jacoby Ellsbury improve the Yankees' outfield defense?

Last season was a weird one for the Yankees. They missed the playoffs for just the second time since 1993, but even stranger, their offense was among the worst in Major League Baseball for the first time in over 20 years. They were not your father's Yankees. However, they were still able to hover around .500 because of a solid pitching staff backed by a cast of aging characters that could still field well enough to counteract their weak bats.

The outfield was more or less stocked solely with players that fit this description. In right field, Ichiro Suzuki fielded brilliantly when he wasn't being an out machine offensively. Vernon Wells did a good job patrolling left field before his bat became too much of a burden. At mid-season, he was replaced by Alfonso Soriano, who performed just as well in the field but provided some much needed pop in the lineup. Brett Gardner was the Yankees' second-best offensive player, but that was by default and not because of anything special he did. Although his work in center field was sub-par for him, it was still better than most everyday center fielders. Curtis Granderson and a long list of marginal players filled in when healthy and needed, but that was pretty much how the outfield shaped up because that experiment in which Lyle Overbay played right field never happened, right?

A look at some advanced defensive metrics shows that this group did the Yankee Stadium outfield grass justice last year. Each of the three metrics below measures the approximate number of runs saved over the course of the year by Yankee outfielders. Data courtesy of FanGraphs and Baseball-Reference.

These metrics were independently developed and calculated so there can be quite a bit of variation between them, but that doesn't mean we should ignore them altogether (that noise you just heard was Joe Morgan slapping my face). Ultimate Zone Rating (UZR) was bullish, Total Zone (TZ) was bearish, especially when it comes to Gardner, and Defensive Runs Saved (DRS) was somewhere in between. If one treats Total Zone's harsh assessment of Gardner as an outlier, these numbers say that the Yankees' outfield saved somewhere between 10 and 20 runs last year. Not too shabby.

Heading into 2014. the Yankees have made a concerted effort to improve by going on a spending spree. Sure they've added a bunch of offense in Brian McCann, Jacoby Ellsbury, and Carlos Beltran, but they also lost one of the most valuable offensive assets in the game in Robinson Cano. Their improvement offensively is likely to be minimal at best. The area where they could improve the most, however, might be in those outfield gloves that performed so admirably last year.

How can that be? Let's make a few assumptions first, namely that Gardner, Ellsbury, and Beltran will be healthy all year and play left, center, and right field, respectively. For each of these guys we can look at the most recent three years of defensive data (2011 through 2013 except for Gardner, who played left field from 2010 through 2012) and calculate the rate at which they saved runs in the field per 1,400 innings played (roughly a full season). Crunch the numbers for each, and there you have a reasonable estimate for how the 2014 version of the outfield will perform:

Holy Rizzuto! That's an improvement of almost 26 runs according to DRS, about 16 runs according to UZR, and more than 44 runs according to TZ. The key here is Ellsbury's presence as one of the best center fielders in the game and its ripple effect in putting Gardner in left field. All systems agree that Gardner might be the best fielder at any position in Major League Baseball when he plays left field. If these two can remain healthy (a very risky assumption), they will be extremely valuable despite their lack of power offensively.

Another thing to take from the numbers above is that Beltran is pretty much done as a useful fielder. Overall, he will probably still provide decent value because of his strong bat, so what if the Yankees took advantage of that? They've proven to have an inexplicable love for Ichiro, so they could easily platoon him with Beltran in right field, then platoon Beltran with Soriano at DH. This way Beltran is still an everyday player, he's less of an injury risk, and Randy Levine still gets to watch Ichiro flash the leather every now and again. Here's how the outfield would look with that configuration:

Depending on the metric, in this scenario the Yankees would improve by at least 25 runs but as many as 47. To put that in perspective, an improvement of 47 runs is roughly the equivalent of adding an All-Star caliber player to the roster. The Ellsbury effect is looking better and better.

Another outside-the-box and unfortunately unrealistic scenario would be if the Yankees decide to make Beltran the full-time DH and instead platoon Soriano with the apple of their eye in right field. After losing his battle with second base as a youngster, Soriano has turned himself into a capable outfielder, even at this late stage in his career. The trick is he has never played right field before, but we can use his data as a left fielder to get an estimate of how he would do there. Here is the 2014 outfield with Soriano instead of Beltran:

Amazingly, the improvement in the outfield could be as many as 53 runs in this alignment. So there you have it. If the Yankees return to the playoffs this year it might just be due to a vast improvement in their outfield gloves as a result of the Jacoby Ellsbury signing.

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