Former Vikings quarterback Rich Gannon predicted that Favre and Childress will "butt heads."
"Brad Childress is a stickler for doing it his way. He's a very detailed guy, doesn't really want to think outside the box, knows what he understands in that system," Gannon said. "Brett's going to come in there, he's going to be hand signaling the receivers, he's going to be trying to change plays at the line of scrimmage, he's going to do stuff that they don't do in that system and he's going to drive Brad Childress crazy."
In fact, Gannon said, Favre might know the system better "as well if not better than Brad."
"When push comes to shove and he's out there in a critical situation in a game, he's going to revert to what he knows and what he's done in the past and it may not be what Brad Childress had thought about or even installed in the game plan," Gannon said