Once Michael has a better understanding of the system, we may seem him active for the game or at the very least a heavy dose of McFadden.
I don't think they want Mcfadden going to heavy until Michael is ready. Joe Randle had a good game, but he's not the best primary back to pound the rock, seems like a 10 touch a game/ third down back/good receiver out of the backfield type guy. I'm not sure there is to much of a difference between Dunbar and Randle to have them both active at the same time.
I'd rather see McFadden starting, Randle or Dunbar as the "Change of Pace"/3rd down back and an active Christine Michael backing up McFadden.
When Michael is ready, this is what we may see.