I'm neither a firm believer in WAR nor a vocal critic of it, but I believe this information is relevant to the discussion at hand:
2011 Morse - 3.3 WAR
2012 Morse - 0.3 WAR
Even accounting for the 44 fewer games played, that's a big dropoff.
Laroche is coming of a career year. 3.8 WAR. I suspect he will fall down to his usual 2.3-2.5 WAR season. So the questions is if Morse can stay healthy and reproduce 2011