wRC+ (weighted runs created, adjusted for park and league). If you want to compare players across positions/years/other variables, this is better than OPS+.
For each position I'll list the top 3 in MLB, and the relevant players at each position (for instance, Doumit and Snyder are injured for the Pirates so I list McKenry, who gets most of the starts now)
Catcher
Top 3 - Napoli 151, McCann 144, Hernandez 134
Central - Hernandez 134, Molina 103, Lucroy 98, Hanigan 93, McKenry 66
First base
Top 3 - Cabrera 167, Gonzalez 163, Fielder 158
Central - Fielder 158, Votto 151, Pujols 140, Overbay 83
Second base
Top 3 - Pedroia 146, Utley 142, Zobrist 138
Central - Weeks 131, Walker 104, Phillips 103, Schumaker 95
Shortstop
Top 3 - Reyes 162, Peralta 148, Cabrera 135
Central - Theriot 82, Cedeno 76, Betancourt 71, Renteria 66, Janish 42
Third base
Top 3 - Youkilis 148, Rodriguez 136, Sandoval 130
Central - Freese 123, Cairo 107, Descalso 95, Rolen 81, Alvarez 67, McGehee 60, d'Arnaud 58
Left field
Top 3 - Braun 176, Holliday 164, Johnson 149
Central - Braun 176, Holliday 164, Presley 148, Heisey 107, Gomes 103, Tabata 102, Lewis 87
Center field
Top 3 - Kemp 170, Granderson 153, Ellsbury 149
Central - McCutchen 142, Morgan 131, Stubbs 110, Rasmus 109
Right field
Top 3 - Bautista 209, Berkman 169, Beltran 153
Central - Berkman 169, Bruce 126, Jay 125, Hart 123, Jones 102
I'd say the main takeaway point is that, while shortstop and third have been major issues, left field is where we lag farthest behind the competition because that's supposed to be a position of major production. At least at short everyone else blows too, and if Cozart can get healthy we'll have a better option (in his limited time his rating was 122). At third, Frazier has potential to help us out as well.
