Purely from a talent perspective, combine or not, there are at best 4 guys (Ridley, Kirk, Penny, Freeman) that I could see pushing their way into the top5 in a few drafts, while Chubb, RoJo, Michel slip out. It seems very unlikely that 1. they bomb the combine and 2. Slip out of those top5 picks. Even if they suck it up at the combine, lots of guys will still have those top5 up there. Just like people had Dalvin Cook that high despite his horrific combine.
I highly doubt we see anyone but those 5 RB's going 1, 2, 3, 4, 5 in 90% of rookie drafts. I can't imagine anyone else to creep into that discussion other than the 4 I mentioned and even that's an extreme long shot. It will be Barkley, Chubb, Guice, Jones, Michel, in some order in most drafts.