If Ricky does come back, and proves to be in game shape, I believe Ronnie will not start for at least 2-4 weeks (all depending on how fast Ronnie impresses the coaches), and will not be the premier back in that time, so he will not get most of the handoffs. But I also believe once he gets in the lineup, he will be at the very least consistent, will have a 4 yards per average, and will run between 900-1200 yards.
I expect him to do much better then 900-1200 yards in the coming years, but this year there will be a new system, a new O-line Coach (That will eventually make that a solid to above average squad), and Ricky might be coming back, so it will be tough for Ron to have a spectacular year running, but he might have one running and receiving with 2000+ all purpose yards.