The main reason is that he was no longer wanted, he was indecisive on whether he wanted to retire or not. The Packers decided to trade him because he wanted to play and they did not want him to play with them anymore.
They didn't think he was going to be as good as they thought he would be.
Because they did not need a Quarterback at the time.
Brett Favre was traded from the Packers to the New York Jets by General Manager Ted Thompson in 2008.
Brett Favre left the Packers at the end of the 2007 season.
Brett Favre was traded by the Atlanta Falcons to Green Bay following the 1991 NFL season
2 - 2.
Brett Favre played 3 hurt games with the green bay packers, i think!!! BRETT WHO????