I said years ago that it was MM. It was Favre's day long meeting with MM that was the last straw that ended his tenure in GB. He met with TT only a short time, but so long with MM that MM cancelled practice that day. Can't for the life of me figure out what they talked about for a whole day. Should have been.

MM; "Hi Brett."
BF; "Hi Mike."
MM; "Brett, I think Aaron is ready to play, and probably won't go into hibernation in the cold like you did in the last game."
BF; "I don't know, Mike; he's damn young with no experience. Heck, I have thrown 10 times as many interceptions as he has completions."
MM; "Believe me, I know that. You ready to compete with him head to head for the starting job?"
BF; "Mike, I'm frickin' BRETT FAVRE! The fan's will have your ass if I don't start."
MM; "My decision to make, Brett. Bye, Brett."

TT would never have gotten rid of Favre without MM being comfortable with Rodgers as the starter. I have always felt MM said it was time.