Who should I trade Manning or Rivers?

I'm looking to trade either Peyton Manning or Philip Rivers to improve my depth at RB because LT is struggling and Willie Parker is hurt. Now Peyton is already ped his bye week which is good but his recent performances coupled with his tough schedule make it hard. Rivers hasn't looked great lately either though and hasn't ped his bye week yet. I also have Reggie Wayne which helps when him and Peyton connect. I have no other QBs on my roster.