Right but there is a difference between taking someone late for depth and using a Day 1 (or is it day 2 now?) pick on an RB.
If they bring in someone with one of the top 64 picks Mack will most likely be relegated to 3rd down/change of pace back. Except he hasn't done well picking up blitzes either so that may not be an option.
If they draft someone in the 4th rd or later its an open competition/lean Mack and he would be looking at more touches. I think most would agree that Mack isn't a Gurley, Bell, or Elliot and will be in some kind of timeshare. It's just is he in a situation where he can look at 50% of the snaps, or will he be put into a situation where he gets 25% at best?