Here's an article from the CCTimes about analyzing managers in Bill James's latest handbook.

http://www.contracostatimes.com/mld/cctimes/sports/baseball/mlb/san_francisco_giants/16875803.htm

"According to a new book by James, Alou summoned 438 relievers last year; Bochy brought in 475.

Alou had 22 so-called quick hooks (pulling a starting pitcher early in the game); Bochy had 43.

Alou left starters in for nine long outings (120 pitches or more); Bochy did it five times."

Obviously the composition of the roster is just as (probably more) important than the manager in determining those stats, but still interesting.