I think you just hit the nail on the head, but what your post does is it explains why the Red Sox pitchers are not as good as the Rays' pitchers.
It's kind of like something I have heard at times about certain pitchers. People will say that he has 1 bad inning per game (about 4 runs), but he is otherwise good. I answer that statement with a question. What do you call a pitcher that has one bad inning per game? Answer: A bad pitcher.