You could say I am skeptical of many of the advanced defensive metrics that are out there. That wouldn't be news, especially since I am in no way anti-advanced statistics -- if you've stuck with me this long since we came to Over the Monster or you have read me in the past, it should be pretty clear I love me some data.
That is why, when Red Sox fan and fellow SB Nation blogger Adam Darowski mentioned on Twitter this morning that Carl Crawford was finally at 0.0 WAR (of both the Fangraphs and Baseball Reference variety), my first thought was to wonder just how little the defensive metrics in both fWAR and bWAR thought of Crawford, and if they were on target with their figures.
Crawford, in his three months on the field for Boston, has been worth -0.7 runs fielding via Ultimate Zone Rating, and is at -0.1 defensive WAR at Baseball Reference. In a vacuum, nothing is particularly striking about that. But throw some context in, and you start to wonder if it makes any logical sense. Crawford, according to UZR, was worth 16, 17, and 18 runs defensively in his last three seasons in Tampa Bay's outfield. What UZR is asking us to believe is that, because he has had to learn how the ball bounces off of the Green Monster in left, he is suddenly not only not playing like a plus defensive outfielder, but is trending negatively defensively in three months time.
Now, I can accept the idea that Crawford, not as accustomed to the nuances of playing left field at Fenway, has played under his actual skill level to this point. But if I didn't trust UZR in Fenway's left field before, then this certainly isn't helping the matter. Without even getting into the matter of all of the batted-ball data problems, and the fact that UZR, even if it is finely tuned mathematically, is stuck in a "garbage in, garbage out" position due to the data it is fed, let's consider that, in Manny Ramirez's Red Sox career, he was rated a far worse fielder at Fenway Park than on the road according to UZR in his career. The Manny Ramirez who had trouble ranging and taking proper routes, but played the ball off of the wall well and was able to play shallower at home due to the smaller space, the Manny Ramirez who could use his arm and quick release to his advantage in the smaller confines of Fenway's left field.
This isn't me saying that Ramirez was all-world defensively at Fenway during his time in Boston -- just think logically about this. Left in Fenway was tailored for someone like Ramirez, as it was able to hide some of his problems, but magnify his few strengths. Why then was he considered so much worse at home, even after park adjustments for UZR? Fenway should be helping Crawford, too -- while he doesn't have the range issues Ramirez did, his arm is his weakest defensive tool, and the smaller left at home games should go a long ways towards hiding that fact; UZR hasn't seen it that way just yet.
Ramirez improved defensively according to UZR after leaving Boston, despite moving to a much larger home park with more territory to roam. Or, to put it another way, UZR rated Jason Bay as worth +1.7 runs defensively with the Red Sox in 2009, despite a history of being about as bad defensively as Crawford was good. Something is amiss with UZR and Fenway's left field, and it makes Crawford's -0.7 value suspect.
This is a long way of saying that Crawford has likely played better than his WAR indicates. Baseball Prospectus's Fielding Runs Above Average (FRAA), which avoids the batted-ball data that can muck up the works in more advanced metrics, but by doing so has taken kind of a back to the basics approach, has Crawford at 2.8 runs above average. In three months time, in a new (and unique) setting, and with his ability, that is more reasonable. FRAA, by the way, has Crawford as a win or better defensively in the past three years, so it's not like the system rates him higher historically than UZR or Baseball Reference's defensive WAR.
It should be no surprise, given that FRAA believes Crawford has been above-average in the field, that he has already been worth nearly a win above replacement overall as well. At that rate, despite his horrid April, Crawford may end up an average season in the first year of his deal with Boston. This may seem like picking the prettiest picture and going with it, but, given the problems with UZR and the questionable drop in Crawford's numbers from last year to this year, it also happens to be the more believable scenario.