Word is that it's a lot of personal issues. He's broke, wife left him, he's sleeping on couches, and drinking too much whiskey, and most of his friends from the past were leeches who abandoned him, or did harm to him in the end.
He won't say it's the hip, but someone I'm acquainted with talked some with him recently says they think that's part of it,. I'm guessing with that much time off the bike, and that long of a recovery, and something no one else has ever done in this sport, it has to have something to do with it, but who knows?
Even if he's completely clean and wasn't in the old days, he still has a huge engine and a load of talent. It's just odd that he's now only a decoy for Sutherland, Baldwin, etc., and finishes way back in the ITT's.