Although Favre's announcement this week came as a bit of a surprise to most football fans, his reasoning — that anything short of another Super Bowl championship would be a disappointment — is sound.
Favre, 38, has nothing left to accomplish in the game. He's won a Super Bowl and is the only three-time MVP in the history of the league.
Favre set the bar high for quarterback play in his 17 seasons in the NFL
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He also owns the three most significant passing records in the game after setting all three in 2007, his final season: passing yards (61,655), passing touchdowns (442) and wins as a starting quarterback (160).
"Brett Favre will always be remembered as one of the greatest players and fiercest competitors in NFL history," NFL commissioner Roger Goodell said in a statement.
There's no doubt about that, and Favre's records, spread over 17 seasons, are a testament to his durability and consistency. He completed 5,377 of his 8,758 attempts — a career percentage of 61.4.
Of course, when someone throws nearly 9,000 passes, a number of those are going to get intercepted, and Favre holds the NFL record for that statistic, too, with 288.
But perhaps the most amazing statistic in Favre's career is the sheer number of games he played. Including the playoffs, he appeared in 275 straight games, and he started the last 253 regular-season games of his career.
Enter the Colts' Peyton Manning, who is putting together the makings of a career to rival Favre's. In 10 seasons as the Colts' quarterback, Manning has shot into the upper echelon of the league's all-time greats. And with Favre's marks no longer a moving target, Manning could get to some of them in less than five seasons.
His 41,626 passing yards place him ninth on the NFL's all-time list, while his 306 touchdown passes place him fourth all-time. His 105 wins as a starting quarterback place him eighth in the league's history.
At his current rate of 4,163 yards per season, Manning, 31, could pass Favre's yardage mark as early as 2013, when Manning would be 37 years old. Manning trails Favre by 136 touchdown passes, but at his current rate of 30.6 per season, Manning could catch or pass Favre by the 2012 season.
The Colts have averaged 10 1/2 wins over Manning's career, and he trails Favre's mark of 160 wins by 55. That means, if the Colts continue to experience the success they have over the first 10 years of Manning's career, he could surpass that mark in 2013. Of course, if the Colts continue to win 12 games or more a season, as they have for -- straight seasons, he could get there even faster.
Manning could pass some of Favre's records in less than five seasons
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Manning's interception pace is one area he probably won't measure up; at his current rate, he would have to play into late 2016 or 2017 and into his 40s to surpass Favre's numbers.
Of course, all of these projections assume that Manning continues his extremely high level of play — an unlikely prospect considering that players begin to decline with age. And, of course, any chance at Favre's records could disappear at any time, as an injury is a constant threat to a quarterback's career.
But even from that standpoint, Manning appears to be the most likely to measure up to Favre. Manning has started every single game of his 10-year career, and that streak — 160 straight — is the second-longest in NFL history.
Of course, that's still 92 games short of Favre's records — nearly six full NFL seasons, which means it would be 2013 when Manning breaks that streak, which he'll only get one crack at. One ill-timed injury, and Favre likely will hold that record for eternity.
The common trait of the two signal callers is that neither plays with an eye on the record book — winning matters most.
Again, assuming Manning stays healthy, Favre will hold his records for around five years, long enough to go into the Hall of Fame with them. Then, it will be Manning's turn.