Mike Cameron played centerfield for the Milwaukee Brewers in 2009. He recently signed with the Boston Red Sox as a free agent. At age 36, Cameron posted numbers very much in line with his career averages, .250/.342/.452 for 2009, .250/.340/.448 for his career. He’s not going to replace Jason Bay’s bat, but the Red Sox hope he’ll improve their defense.

Over the last three seasons, Mike averaged about 10 runs prevented defensively. Bay averaged about -14 in that time in the easier leftfield. So the Red Sox are looking to gain about 24 defensive runs with the move. That should balance out the 22 runs they’re losing offensively.

(Due to the shape of the winning percentage curve based on runs scored and runs allowed, teams gain more wins by trading offensive runs for defensive runs, so this is a good move.)

Cameron is an interesting defensive player, because he tracks balls differently than most outfielders. He runs to where he believes the ball will land, and is such a good judge of the ball off that bat that he’s usually right. He does get it wrong from time to time, however.