I don't know who to start, should I bench Randy Moss?

I have 2 Wr positions and 2 rb positions and 1 rb/wr position: Right now I have in Santana Moss, Eddie Royal, Tim Hightower, Benjarves Green-Ellis, and Reggie Bush in. On my bench I have Randy Moss and Ricky Williams. Do I keep out Randy for Royal? Also, I have Ben Roth. in, or should I put in Rogers both have been really unpredictable lately?