When Miller went in, everybody in the stadium was watching him. Forget the fact that they nearly scored on the play, everybody was talking about how he threw the defender in front of him aside like a toy.
I think the coaches are still not 100% confident in his pass protection skills. His run blocking is pretty darn good, though. While platooning o-linemen is not usually done, they may decide that his run-blocking is so dominant that the run game struggles without him and put him in the game for running situations.
Or not. What the hell do I know?