In Sunday's New York Times, Alan Schwarz writes about John Dewan's Fielding Bible, Aaron Rowand, and how Rowand's absence will effect the White Sox pitching staff. I had no idea that Dewan was a White Sox fan.
As for the rest of the article, I respect Dewan's work, but I don't think anyone should trust one fielding metric implicitly. The article mentions that Rowand was the best outfielder in baseball last year with a (+30) rating. Pinto's PMR and Gassko's RANGE both rated Rowand highly, but had others in the top slot. Does that mean they are wrong? No. When trying to quantify defense, right now, there is no right answer. And if there is no right answer, we can't be throwing around numbers to claim anything more than so-and-so is a good fielder and what's-his-name has the range of a statue.
Rowand was a very good defender last year -- everyone is in agreement on that -- but the metrics aren't precise enough to accurately quantify how his defense differed from year-to-year and how his defense can be projected in the future, which really makes them limited for the purposes of assessing the effect of a departed player. The White Sox case is even more difficult to quantify when you factor in the fog surrounding Brian Anderson's defense. Anderson has played only 36 innings of centerfield in the majors, so there is no statistical significance to any of his fielding numbers. That doesn't stop BP from trying, rating Anderson as essentially average.
At this time last year, you would have had a tough time convincing most people around baseball that Rowand's name belonged along side those of Torii Hunter, Jim Edmonds, and Andruw Jones; just a year later, and you'll find many of those same people can't fathom the White Sox succeeding without him. It's amazing to me how one series in New York has seemingly transformed him into an elite centerfielder in the eyes of the baseball community.