There's never been anything in the NFL quite like what Brett Favre is doing this season.
He's having an MVP-caliber year at the age of 40, a feat no previous quarterback has accomplished.
Favre ranks second in the league in passing efficiency (106.0), completing 68.1 percent of his passes for 3,341 yards, 27 touchdowns and six interceptions heading into Sunday's 8:20 p.m. kickoff against the Carolina Panthers at Bank of America Stadium.
"You don't see 40-year-old quarterbacks playing like they're in their prime, like (they're) 31 years old," said Eugene Robinson, the Panthers' radio commentator who played with Favre in Green Bay in 1996 and '97. "He's a kid, man. Brett doesn't think like (other people)."
Favre is the 17th quarterback to play in the NFL beyond age 40, according to the Pro Football Hall of Fame's Web site, but most of the others were in backup roles at the end of their careers.
There were two previous times when quarterbacks 40 or older had 2,000 or more yards passing. In seasons when they turned 41, Vinny Testaverde threw for 3,532 yards, 17 touchdowns and 20 interceptions for Dallas in 2004, and Warren Moon threw for 3,678 yards, 25 touchdowns and 30 interceptions for Seattle in 1997.
Favre has a chance to approach 4,000 yards this season with far fewer interceptions than Testaverde and Moon accumulated.
"He's operating as well as I've ever seen him operate as far as where to go with the ball and when it does go, being on target," said Panthers coach John Fox. "I think he's having a remarkable year."
Favre is surrounded by a splendid supporting cast, including offensive and defensive lines that are among the NFL's elite, arguably the league's top running back in Adrian Peterson, and a talented young receiving corps that includes former South Carolina star Sidney Rice and rookie sensation Percy Harvin.
"I've seen Brett have some exceptional seasons, and I've seen him have some dismal seasons," said Carolina receiver Muhsin Muhammad, a 14-year veteran.
"I think his motivation right now to play the game is extremely high. You can tell (that) on the field. He's playing with a lot of passion. He's making throws (that) not a lot of NFL quarterbacks can make. You can tell he's healthy."
Favre was precisely what the Vikings needed to go from good to potentially great. After a 10-6 playoff season last year, about all they lacked was a superior quarterback.
Now, they bring an 11-2 record to Charlotte to face the 5-8 Panthers.
"He's been a great addition, a great piece of the puzzle," said Vikings coach Brad Childress. "He's been a good teammate in the locker room, right from the get-go. The thing I found out about him is that he is an unbelievably hard worker.
"I knew about his physical skills and how he played the game, but you have no idea until you work with somebody what kind of time they spend at their trade. It might be late hours or after everybody is gone, or back here on a Saturday when nobody is here, but he spends a lot of time here."