When we focus on the individual play of the players for this Celtics team, we tend to forget that this team more than any other in the NBA relies on a collective approach to winning. We've seen this before where the balance, particularly offensively, gets a little off and guys start looking worse. Then we look for blame to place. Rondo, Pierce, KG, Ray, even Curly now.
I think the truth is everyone is affected by each other's play and guys start looking for a rhythm which is outside the way this offense flows when it's playing well. These guys have been through this before, and been together too long to not know how to fix it.