I'd go with Knowshon.
Arizona is a pass happy team. Even if Bouldin's gone, they will still have two 1000 yard receivers on the team and as long as the ageless wonder is taking snaps and getting hip replacements, they'll stay that way. If they try to hand the reins to Matt (again), then they'll need to lean more on Beany, but until then, he'll be splitting carries with Hightower...what little carries there are.
I know Denver is moving to a more pass focused offense with What's His Name bringing the New England offense over, but they don't have to QB to lean on for that. Ole Neck Beard is a pretty good QB, but not one that can be leaned on. Knowshon is an every down back and I think he'll step right in and run the rock well.