You said it's been my theme and I'm going to assume you're not talking about the arts, ie, Music, Movies, or Literature so it should be safe to assume you mean my thoughts, which is the only definition of theme that would apply here.
It isn't my thought that he's not been a good player, it's a fact. You would trade something for a backup catcher? That isn't a good use of resources, he's much closer to McCann with the bat than he is to the guy that Texas traded to replace him.