FWIW Bills' C.J. Spiller enters tough market for running backs However, Buffalo has the market in its favor. Running backs are one of the NFL's most disposable commodities. Last year's top free-agent tailbacks -- Ben Tate (two years, $6.2 million), Maurice Jones-Drew (three years, $7.5 million), Darren McFadden (one year, $4 million) and Knowshon Moreno (one year, $3 million) -- all received team-friendly contracts.