I think he was pretty disappointed with the results in 2013.
so he has made some changes:
1. he removed his coach from the facilities
2. he started trying new racquets
all indication is that he wants to come back a lot stronger in 2014. his best results at a slam are likely to come at Wimbledon.
there is no question he still has the game. what he does not have is the consistency, fitness, and the confidence.
he needs all three so there is much work to be done in the off season.