'It's time,' he admits after watching the Minnesota Vikings' last game of the season from the sidelines.
Finally, the end of the line for iron man Favre
Brett Favre was the NFL's ultimate iron man for 19 years, inspiring coaches and teammates with extraordinary toughness and thrilling fans with a daredevil's verve and a showman's sense of the moment.
Yet the once-irrepressible Favre never looked older or more fragile than in year No 20. The magic of last season, and most of his brilliant career, never seemed farther away.
It had to end some time. And Favre says that time is now.
The 41-year-old quarterback sat out Minnesota's season-ending loss to the Detroit Lions on Sunday because of a concussion, and it appears his career ended not on the field trying to rally the Vikings to another victory, but on the sideline as a third-string rookie floundered in Favre's place.
No one - not even Brett Favre - can play forever.
"I know it's time, and that's OK. It is," Favre said after the 20-13 loss. "Again, I hold no regrets, and I can't think of too many players off hand that can walk away and say that. Individually and from a team standpoint, it was way more than I ever dreamed of."
He also retired in 2008 with the Green Bay Packers and 2009 with the New York Jets, only to return both times when the football bug bit him in the summer. He knows that there will be doubters again.
"I don't know for me if it's ever easy," Favre said. "I'm sure throughout this year, the comment has been made that, 'We'll wait and see in August or September' and that's fine. It's time. I'm OK with it."
There appears to be one big difference this time. Even if he did want to come back next year, would anyone want him?
The Vikings are going to start over. And the market for a 42-year-old quarterback coming off one of his worst seasons - both personally and professionally - doesn't figure to be hot.
If this indeed is the end - for real, this time - for Favre, one of the most colourful and celebrated careers in NFL history concluded with a season filled with interceptions, injuries and insults.
He threw 19 interceptions and his 69.9 quarterback rating is the lowest of his career.
The Vikings sunk to the bottom of the NFC North after starting the season with Super Bowl aspirations, Brad Childress, the coach, was fired during the season and Favre was fined US$50,000 (Dh 183,650) for failure to cooperate with an NFL investigation into allegations that he sent lewd photos and messages to a game-day hostess when both worked for the Jets in 2008.
Favre's reputation took a serious hit from the humiliating scandal, which tarnished the image of one of the league's most popular players.
He declined to comment on the fine after Sunday's game.
Favre's long-awaited union with Randy Moss, the receiver, also was a spectacular failure and his cherished record streak of 297 consecutive starts ended three weeks ago, with a sprained throwing shoulder making it impossible for him to let those famously zip-filled passes rip from his right arm.
And just for good measure, the Metrodome roof caved in, forcing the Vikings to play "home" games at Detroit and at the University of Minnesota's outdoor stadium in December.
"It's been a wonderful experience for me," Favre said.
"This year did not work out the way we would have hoped, but that's football. I don't regret coming back. I enjoyed my experience here."