Experience as a RB is not important. You need to know the playbook, that's very important. Understand pass protection, when to release, route trees, all that stuff. It's an instinctive position, though, really about the easiest non-specialist position to come in as a young player and succeed.
That's why if you're Bell or Ozigbo or really any of these guys, you're looking over your shoulder at Washington. If he's as good as everyone says, he will be hard to get off the field. As he learns more and more, he stands to get more and more reps. Coach Held has talked a great deal already about getting him up to speed, learning how to be a college athlete, learning the playbook. They know what they got there, and they'll work hard to get him to a position where he can succeed.