Djokovic is making a smart move by playing.
Djokovic has little to lose but if he can stop Nadal from getting a win at a tournament he's owned....
Fed should skip this one, he's played a lot and the upcoming schedule this year is very heavy with the olympics in the mix.
He's letting the others use up their energies and possibly having problems later due to being overworked.
He can still get in as a wild card if he wants.