A good role for Ingram might be as "the closer'', fresh legs in the 4th quarter. I hope we sign Michel. I think the rookie Smith might also factor in the run game as well.
Yeah, I'm not counting Smith out. I just don't want to count on him to develop into a guy that can share the load this year. Ideally you add Michel and have Kamara, Michel, Ingram, and Smith at RB. That way you have depth in the event of a Kamara suspension combined with some experience, leadership, and youth.
And, yes, I could see Ingram in that close role coming in fresh near the end of a game so that he can get a bunch of quick carries and get in rhythm. Ingram always struck me as kind of an old school RB that took a few carries to get into rhythm. The closer role would be perfect for that.