Really, I think his spirit is just broken. He's older now, and he knows this team isn't going anywhere. I wouldn't be surprised if he's secretly opposed everything Pop has done this year, but since he's a trooper he obviously isn't going to say anything aloud about it.
I can't say I blame him, but the transition from perennial contender to 1st round fodder can't be easy. Plus, with the all excitement going into this season, it's hard to say the dissapointment isn't anything less than mind numbing.
Or maybe he's just hurting and not saying anything