By all accounts, Garver is still a work-in-progress defensivly. He's getting there, but he isn't there yet. He has 5 passed balls so far this year. Not that that by itself says much, but the scouts are the ones saying he isn't there defensively yet.
Of course he ended up pinch hitting in the 7th yesterday. So, he really wasn't off. And if you think he doesn't need it, you haven't been watching him swing the last 4-5 days.