RB is more about opportunity than skill, and is one of the easiest, if not the easiest (certainly on offense) positions to plug and play, as long as the candidate is able to learn the pass pro blitz pick up calls/hot route outlets pretty quickly.
IMHO, an RB going from one team to another, late in training camp, and in this case in particular, Robinson to the Bears (Lovie Smith) isn't something I'm too concerned about.
I think he could do ok in a tandem with Swift, but as an NFL COP back with minor FF relevance only.
David Montgomery, BRob is not.