I have been advising some of my friends and family who are Rafael Nadal fans not to get too excited about Nadal returning in the Abu Dhabi exhibition and then perhaps playing Doha and the Australian Open.
1. He hasn't set foot on a court in quite a while.
2. Once he starts practicing on hard court ( I'm betting he does, even though I would still recommend clay at first), there is no guarantee that he won't suffer another setback where he continues to say he is not in the right condition to play.
3. Even if he plays in the exhibition, it is no guarantee that he'll be fine for the tour events.
My advice is wait and see. If he can play in the exhibition, and some tournament like Doha or other prep, then with some luck, he might be able to do ok in the Australian Open. But we have to be realistic too. It will have been 6 months with no tournament play. From what I've seen of Nadal in the past, he needs lots of work to have his big swing in tune.
In my opinion, he will be lucky to be in top shape for the European Clay season. Unless he really needs the money, and if he serious about getting back to his best with the least chance of injury, my advice would be to stay out of these hard court exhibitions and tournaments, yes, even the AO, and practice only on clay until February. If he is still healthy at that point and is able to play, then he should go to South America and play a 250 event(s) like in Brazil and/or Buenos Aires, then Acapulco 500 event, skip Indian Wells and Miami, then play Davis Cup (if they beat Canada in Feb, they will have home court April 5), and then go to Monte-Carlo April 15, and Barcelona, skip Madrid, then play Rome and Roland Garros.
Would he ever do that? Who knows?