Charles, MJD, Ridley?!?

[futurepro62]

Ok so I have 4 running backs who could easily start on any team. I can play three of them in my league. I picked up Spiller and feel like he is a must start until he slows down or Jackson comes back, then I have MJD who I feel I have to start because he was my first rounder, so my decision is really coming down to Ridley playing Baltimore or Charles playing the Saints. Ridley has been good and Charles has been bad but playing against the worst running defense I feel like I should start Charles. Any thoughts?