The issue of Favre's stamina

Posted by ESPN.com's Kevin Seifert

Those hoping to wrap up (Brett) Favre Watch '09 didn't get much help Monday from Minnesota president Mark Wilf, who acknowledged the Vikings' interest and refused to rule out the possibility of signing Favre sometime this summer.

The Vikings' intentions seem clear. Favre, on the other hand, is weighing options for his partially torn right biceps. He has no doubt considered the implications of playing for a chief rival of his former team. And as Favre approaches his 40th birthday, I wonder if he might also be pondering the way he has run out of gas in each of the past four seasons.

There has been significant discussion surrounding the impact of Favre's partially torn biceps tendon on his performance last season, a point Scouts Inc.'s Matt Williamson made last week in analyzing Favre's potential comeback. In the same post, reader Robbiemustgo32 produced a startling statistical compilation that reveals a dramatic end-season drop-off dating back to 2005.

The chart below illustrates Favre's performance before and after the 12th game of the past four seasons. Just for the fun of it, I verified Robbiemustgo32's figures, even though I'm far more likely to botch a chart than most readers. Everything added up.

Robbiemustgo32's work illuminates a trend that began long before the biceps injury surfaced. You'll note Favre's completion percentage dropped nearly nine points on average after Game 11, and he threw nearly three times as many interceptions (34) as touchdowns (13) over the combined final stretches of those seasons.

In truth, some of the NFL's best quarterbacks fall off to a degree at the end of the season. The reasons make sense. Weather conditions worsen. Injuries occur, hampering the passer and/or limiting his weapons. Defenses make adjustments. Playcallers grow more conservative.

So to be fair, I worked up the same analysis for the six quarterbacks originally named to the 2008 Pro Bowl. (Favre was one of them.) Take a look:

Only one of the six, Indianapolis' Peyton Manning, improved in every category over the final five games of last season. Everyone else leveled off in at least some categories, but none dropped as precipitously or as across-the-board as Favre has since 2005.

Arizona's Kurt Warner, for instance, kept his comp
letion percentage at 60 percent and maintained a positive touchdown-interception ratio. Meanwhile, New Orleans' Drew Brees still threw twice as many touchdowns as he did interceptions.

So what do these numbers tell us about Favre? From the outside, at least, they reveal a simple but valuable fact: He hasn't had the stamina to maintain acceptable production over a 16-game season for some time. Favre will turn 40 on Oct. 10, and while he has considerably outplayed younger quarterbacks in recent years, his bionic arm and body have revealed their limitations.

More than anything, those issues can be traced to cold weather -- a key factor that both Favre and the Vikings must consider. Although Minnesota could play as many as 11 games indoors this season (depending on retractable roof decisions), it has two outdoor games in December that figure to have significant impact on the playoff race:

  1. Dec. 20 at Carolina with an 8:20 p.m. ET kickoff

  2. Dec. 28 at Chicago with an 8:30 p.m. ET kickoff

According to STATS Inc., Favre has played 14 games in weather under 40 degrees during the 2005-08 span we've been analyzing. In those games, he's thrown nine touchdown passes and 25 interceptions while compiling a 60.3 passer rating.

In eight indoor games during times when the outdoor temperature was less than 40 degrees, Favre threw 15 touchdown passes and five interceptions while compiling a 99.9 passer rating. (Also based on STATS research.)

There are many reasons why Favre has waffled on whether to retire or continue playing in recent years. Without a doubt, one factor must be the way he has finished those seasons from an individual standpoint. His end-game performance, coupled with the potential for cold-weather games on the Vikings' schedule, adds another layer to a discussion that -- as Williamson originally pointed out -- has no slam-dunk resolution.