I had Rodgers in 2 leagues, 1 of which I made the playoffs in (after the worst draft in history, I picked up the following free agents: Peyton Hillis, Brandon Lloyd, Michael Vick).
I wouldn't call the matchup against New England a "nightmare" for Rodgers at all. The Patriots have given up the 2nd most passing yards in the NFL and with their offense kicking... GB would certainly get a lot of chances at the very least. If Rodgers plays you have to start him...
I have Eli Manning as a backup so that's probably my best bet... of your options I would probably go w/ Garrard against the Colts. Barring that maybe Collins?