Why are you asking me? why does any player get traded, released, dfa, not resigned? we see a lot of other reasons that don't equate to "he stinks". I don't know the answer to your question, but I do not McGuire is a plus defender, and at this point in his career entering his age 28 season he's actually put up better offensive numbers than Vasquez did up to age 28. Now that might not mean anything, but we do not Catchers are notorious for being late bloomers with the bat. McGuire doesn't have to be a plus bat. If he has a .680+ OPS with the bat and play plus defense he's fine hitting 9th. If he takes a step forward with the bat then that's amazing.
Personally, I wanted to make a run at Contreras.