1. Is there reason to worry yet?
2. How much of this do you blame on Doc?
3. What should they do (if anything)?
1. There is a reason to worry, be concerned, and be pissed. But with that being said the problems can be fixed. The age isn't the problem, it's the lack of fire in the second half. Doc will have to find a rotation to stop other teams when the Celtics fall into quick sand. The Chemistry isn't there and that is something falls directly on the players and coaches.
2. Doc Rivers needs to take some heat. He should be able to find a way to devise a plan to hurry up the chemistry issue. I think the biggest mistake the Celtics have been doing the past 2 seasons is not do a team building thing, like they did the first year the big 3 came when they went to Europe. He needs to be more drastic with who's playing and who isn't. If KG isn't playing well bench him, and the same can be said for the rest of the players. If I were him, I would start throwing hissy fits Pete Bell style. They are playing like shit, have them feel like shit. Don't take the Terry Francona approach when it comes to incompetence. Have Daniels or Tony Allen start and push Ray to be a 6th man.
3. What can they do? Nothing. Ride the wave. Even though they have hit a terrible snag, there is no way we can improve this team by trading Ray Allen. (I'm kind of worried the Cs kept Ray out of the lineup last night in order to trade him so he wouldn't hurt himself playing) This is a championship team right now. If they all play like they can, no one will be able to beat the Celtics. The pure talent on this team is endless.
I mean lets face it, the Celtics are going to be in the playoffs and might be a 4 seed. Who cares, I'd rather have a healthy team and be a higher seed then a team that is injured going into the playoffs, but has home court.