He's up for good. And he WILL be a C. That's why he was in AAA, to work on his defense. I'm willing to bet he gets the majority of starts.
I find it hard to believe that one month in the minors did the defensive trick. I'm guessing they decided he'll never be a great catcher and he'll get playing time, just not at catcher most of the time. I might be wrong on that but I don't think he learned defensive skills in a month.