EXACTLY.  In the 4th quarter when you're up 35-17, that's the time to put De'Angelo Henderson in the game and get him live reps.  He hasn't had any in the regular season and CJ's already carried it 20+ times, why burn out your lead back and why put in Charles who we need to be careful with?  Get the rookie in there and let him churn it out and get valuable game experience.