Too much money for such a huge injury risk (chronic foot). Thumbs down. Use the draft for a RB. It will be cheaper. Spend FA money elsewhere for a position tougher to fill. Backs are a dime a dozen and given the right scheme and OL, you don't need exceptional talent for success. Case in point: NE Pats. They have had average backs for years (Green Ellis, Ridley, Vereen, to name the most recent unspectacular backs) but have displayed tremendous production from the position.
Spending a 1st round pick or using a ton of free agent money for a RB (unless it's a talent like Peterson) is just fiscally irresponsible for most NFL teams.