Was your point that every pitcher for the Sox was a back end starter?
If so, then I agree.
However, I believe the problem was the lack of production from the front end of the rotation.
There's no beef on my part. Just don't think going into last season Beckett would have been considered a 4 or 5 by anyone. Calling him a back end of the rotation starter just doesn't make much sense and confuses the point you were trying to make.