Originally Posted by moon language
If he returns to his prior top level then he could definitely win another slam on hard. It won't be any more or less likely than it was before, which is to say, it will still be very difficult for him and he'll need things to fall in the right order.
Returning to his previous top level, on any sort of consistent basis, is unlikely although he could win one if everything goes his way AKA USO 2012 and or he finds his top level for a couple of matches. If Nadal plays, for say another four years, then he has a decent chance of winning one more non clay slam, which will most likely be Wimbledon.