When I visit player pages on Baseball Reference, I frequently check the similarity scores down near the bottom of the page. Similarity scores are a Bill James invention, a formula that starts at 1,000 and subtracts for statistical differences and includes a positional adjustment.
Because of the positional adjustment, the closest comps are generally players of similar position. Example: Greg Gagne, the shortstop of the 1987 and 1991 World Series winners. His 10 best comps are eight shortstops and two second basemen, including two of his predecessors as Minnesota's shortstops (Leo Cardenas and Zoilo Versalles). His closest comp is Mike Bordick, whose career overlapped with Gagne's. Bordick's closest comp is Gagne, and his top 10 includes five of Gagne's top 10.
Anyway: When I was doing last week's series of posts about catchers on the Hall of Fame ballot, I glanced at the similarity scores for those guys.
Jorge Posada's list is topped by five catchers, starting with Lance Parrish and including a pair of Hall of Famers (Gabby Hartnett and Gary Carter). Then come four middle infielders (one in the Hall), followed by another HoF backstop (Bill Dickey). None of them, by the way, is a particularly close match for Posada (860 is the top score); James has said that that is often the case for a Hall of Fame caliber player.
Ivan Rodriguez's list is headed by Pudge 1.0, Carlton Fisk, and includes three other catchers (Ted Simmons, Carter and Yogi Berra). Fisk's score is 818, which isn't very comparable at all. Pudge 2.0 was a unique player.
Jason Varitek's best comps are all catchers, and the first nine are more comparable to him than anybody is to Posada. None of Varitek's comps are in Cooperstown.
A.J. Pierzynski has six catchers and four middle infielders in his comps. Two Hall of Famers, as I mentioned in an earlier post.
And Joe Mauer has ZERO catchers in his comp list. No. 1 is Dustin Pedroia. The next two are Hall of Fame shortstops, Lou Bordreau and Travis Jackson. Then come a bunch of infielders whose scores are rather distant.
(Pedroia's best comp is Mauer, followed by a bunch of second basemen.)
It's really odd to see a catcher with no catchers in his comp list. But as I've said often, Mauer is a historically unique figure. The catcher I've long thought of as the Mauer prototype is Mickey Cochrane, Hall of Fame catcher of the 1920s-30s. Mauer is No. 5 on Cocharne's list, which contains nine catchers and Boudreau (four Hall of Famers in all, plus Mauer and Yadier Molina). But nobody scores particularly close to Black Mike either.