I read an interesting article the other day. The Pack doesn't want Brett back, but they don't want to trade him to a division rival either... so he's not good enough to start, but he's too good to play against.
But anyways, the guy said... why not TRADE him to the Vikes? They'd get the Vikes first rounder (and possibly more), and if they really think Favre isn't better than Rodgers, then they get a chance to prove it twice a year. Plus, generally speaking, the Vikes are an older team... with no first rounder (and possibly another pick), a young team like G.B. is poised to own the division for a while as the Vikes get old overnight.
Food for thought.