Peter King has a very insightful look into the past year of Brett Favre's life. It is worth a read. He offers a similar hypothesis to the one I shared on this site as to why his play took such a dive late in the year.
This is what I think: Before the 2007 season, Favre spent eight weeks with Ken Croner, a trainer from Athletes Performance Institute; Croner actually lived in Mississippi and trained Favre in his home. When Favre went to camp in Green Bay in late July 2007, he went knowing he was in the best shape of his life by far. Last summer, Favre thought he wasn't going to play, and so he didn't do any physical training in the off-season. As time drew close to camp, he threw with the local high school team a few times, but that was too little, too late. Looking back, you could almost predict that, at 38, something would go wrong with him physically at some point of the season, and it did. The only way Favre could have ensured peak performance -- or at least given himself the best chance -- was if he had another two months with a trainer like Croner. At that age, the only way a great player has the chance to be great for one more year is through off-season dedication. That's the biggest hidden factor in why things spiraled downhill so fast for Favre after Thanksgiving.
"John Elway, as long as he's been out of the game, could go out and win a game tomorrow, no question,'' Aikman said. "One game. But that's not the test of a quarterback. The test is being out there for 16 games, then hopefully the playoffs. That's what Brett found out this year. He made it through, what, 11 games? But football's a long season.''
Retiring athletes always say the competition never gets old, but the grind eventually drives them out.