Week 2 Fantasy, can't decide who to play in my flex pos.?

I have a receiver/rb flex position and am having trouble deciding who to play there. for my other 2 receivers I have Holt and Berrian, for my 2 backs, I have Gore and Westbrook. My options for the flex are: Jamal Lewis, Hines Ward, Cadillac, Chris Chambers. Usually I'd play Cadillac, but he's questionable, so my only other rb is Lewis, but I'm not sure he's going to score more points than the other receivers I have available.