Curtis Granderson's excellent night of defense brings up the question once again: just how good is he (or isn't he) defensively?
You would think, in an era when we have endless amounts of data at our fingertips, that we could answer the question posed in the headline in a matter of minutes. And for some, that data might be enough. But as we've talked about before, advanced stats don't always agree with each other, and can paint different pictures of a player.
One of the reasons the different ways of measuring wins above replacement (WAR) don't match up all the time is due to the defensive inputs in the respective systems. Curtis Granderson is one of those players, as, depending on which system you look at, he was somewhere between average and terrible in 2011, defensively.
Baseball Reference has Granderson at -2 runs defensively on the season, or one-fifth of a win lost with the glove. FanGraphs, which uses Ultimate Zone Rating (UZR), has Granderson as costing the Yankees more like half-a-win. Baseball Prospectus's Fielding Runs Above Average, which uses play-by-play data rather than batted-ball data to come up with its defensive figures, has Granderson at minus-13 runs, essentially a win and then some lost on defense.
Granderson isn't alone in disagreement among defensive numbers, but his case is intriguing for a few reasons. He's considered a better defender by scouts than he is given credit for by UZR, FRAA, or the Plus/Minus system employed by the Fielding Bible, which rated Granderson as one of the worst in the game heading into 2011. Ken Rosenthal reports that the Yankees' internal defensive system rates Granderson as above-average, something that systems like UZR and FRAA occasionally spit out as well.
There have been numerous ideas put forth trying to explain the discrepancy between Granderson's perceived ability and the results in the advanced metrics. The one that makes the most sense is positioning, as pointed out by the Wall Street Journal's Dan Barbarisi in August: Granderson plays to right-center, rather than straight-center, thanks to the presence of Brett Gardner, one of the more ridiculous left fielders you'll see. Gardner takes balls away from Granderson, and while those lost plays don't exactly count against Granderson, they are plays that simply aren't available for him to make -- something that would hurt his numbers, as the creator of FRAA, Colin Wyers, says:
If Gardner is taking plays that Granderson would make with an average left fielder playing next to him, that would depress his fielding numbers, although I'm not sure by how much.
There are too many questions surrounding something as nuanced as positioning for Wyers to give an exact answer here, and that's because defensive numbers -- at least, those that are public, as we don't know what every team uses -- just don't have enough input in them to give us the exactness we would like.
Despite the shift, Granderson is responsible for the same zones as all other center fielders. While it's true that he's not debited for plays that Gardner makes in Granderson's zones, Granderson also does not get the credit for those plays. Since UZR compares players on a positional basis, Granderson's low UZR might simply be the product of him not making the same number of plays as his fellow center fielders. Since poor left fielders flank many of them, they have more opportunities to improve their UZR scores by making plays in the left fielder's zone. Granderson has no such opportunity. Gardner is responsible for those zones, and he typically makes the plays.
This shifting of Granderson to right-center can be confirmed by scouts, as well. As one scout put it, "[Granderson] is average. Gardner steals balls to his left, and right-center field at Yankee Stadium is small, so it's hard for [his] range to look good."
Another talent evaluator says that last night's play, in which Granderson bailed A.J. Burnett out of the first inning, was representative of Granderson's defense on the whole: "I like him a lot as a player and a defender but I understand where the numbers are coming from as well. Let me give you a great example. Last night, bottom of the first , he makes a catch that saves the inning -- and maybe the game -- for Burnett. Watching the game, and later confirming with replay and TiVo, it appeared that Granderson initially broke in on the ball, but he's so athletic and graceful he was able to get back and make a play that very few center fielders can make. I think that play is a microcosm for him as a defender."
He's similar to Jacoby Ellsbury in that regard, though our talent evaluator says that Ellsbury has "slightly better instincts." Ellsbury, after a 2009 campaign in center that looks a lot (via UZR) like Granderson's 2011, was worth a win-and-a-half with the glove this year.
This tells us something else about defensive stats that people often forget -- players can slump on defense, too. If you're a Granderson or an Ellsbury, and you have trouble with making reads or knowing what route to take immediately, you're going to have years where your athletic skills and speed are not enough to save you on every play, and then you'll have a 2011 like Ellsbury. Or a 2007 like Granderson's, when he was worth just as much as Ellsbury was this past year.
It's safe to think that Granderson is better than his FRAA and UZR suggest, but that is not to say he can't have a season where he performs poorly. There are extenuating circumstances, such as Gardner to his left and poor reads, but this is a situation where, even with all of the disagreement, everyone is right to a degree. It's hard to accept that vagueness, considering the tools at our disposal, but that's where defense is right now.