Bob Condotta of The Seattle Times discusses the Washington RB options should Chris Polk do as expected and declare for the NFL Draft. While it's noted that Jesse Callier will get first crack at the gig, it's young Bishop Sankey that may have the highest ceiling.
Look for Polk to bolt, and Callier and Sankey to battle this spring and summer. If you need to protect one of the two then I like Sankey based on the limited action I've seen from both.