This rumor makes no sense to me. Brees is one of the best QB's in the league. He's been good for two years now, and his prime is still ahead of him. By all accounts, he is expected to fully and quickly recover from his injury. So why would he want to go to Green Bay, where the Favre situation is still uncertain and the "QB of the future" is already waiting in the wings?
It makes even less sense for Green Bay. Even if Favre retires, they would be investing a lot of money in the QB position. There are only two scenarios where Brees would be worth considering:
1. Thompson is trying to pressure Favre into a decision. This seems kind of low-class to me, but I guess you never know. Business can be brutal sometimes. But on the other hand, I think it would really get Favre teed off, and I doubt that Thompson wants Favre's relationship with the Packers to end on that note.
2. Thompson knows that Favre is going to retire AND that Aaron Rodgers is unlikely to pan out. But considering that Thompson drafted Rodgers in the first round and that QB's take a few years to develop, it's unlikely that Thompson would give up on him already.