Trevor Plouffe does have 105 ML home runs and a career OPS of .713, but I have not really seen much from him in his short time with the Phillies.
I agree that you play to win as soon as possible, but the manager also has to consider the possibility of an extended game. I always hated seeing a good hitter taken out in a double switch in a game that could well go extra innings. I agree, most all managers do it in the NL.