It probably won't help either that it'll also be competing against March Madness for the first two weeks it's back.
Since NBC is most likely done with Community after this season, I guess it doesn't matter how bad it does coming up (and it's a good move to get 30 Rock away from The Big Bang Theory). If Community was doing badly in the fall, I can't imagine how terrible the ratings are going to be with American Idol as added competition.
I love Community, but I think NBC is going to be wishing they had ratings as terrible as 30 Rock's when they see what Community pulls in from here on out.