Favre starts out mediocre, plays very well in weeks 5-8, collapses in weeks 9-12, and the bottom falls out in weeks 13-16. Here are the seasonal splits:
The more he throws, the worse he gets. He needs a strong running game now to rest his arm but that looks like a real longshot this year. If you happen to draft Favre for your fantasy football team, the data strongly suggests getting rid of him after midseason.