I'm not the biggest fan of Keller, but relying on his 2012 as a true indicator of his abilities is a mistake. He was not healthy for about 80% of the season.
I'm interested to see what RBs get in FA this year. Bush has some value, but I can't see a team look to make him their feature back. And Shonn Greene, while not being what we really needed, has some value too. But again, no team is making him their bell cow back. I guess I could see him getting Michael Bush money. And Reggie probably a bit North of there....but not too much more.