Picking Djokovic, but a Murray in his half may give the opponent a chance in the file.
Physically seems fittest and has most endurance of the top 3 which is essential at the event with "Stupid Saturday". Federer used to have it before, but no longer feel he does.
If we have a Federer-Murray semi-final and a Djokovic-Ferrer semi-final on Saturday, I can easily see Djokovic having a comfortable 3 set win and Federer-Djokovic going 4/5 sets. Nadal's injury means the draw is going to be too biased infavour of whoever does not face Murray out of Federer / Djokovic. I expect the betting favourite at the tournament start from Federer / Djokovic will be the player without Murray in their half of the draw.