Hmmmmm, thats tough, none of them are going to get you outstanding numbers. Lynch Vs. Pittsburgh D in Pitt is not going to be good. Moore didn't play last week cuz of injury, but it looks like he might play this week. With Colston out, Moore could get a lot of looks, but Vs. a stingy Bears D, he could also get shut down.
I say it's it's between Branch and Edwards. I would go with Branch, since it's most likely going to be a high scoring game between SD and NE. Brady likes to spread the ball around, so Branch could put up numbers like he did last week, and possibly a TD.