Favre's fall latest blow to image of all-American hero

After Woods and Armstrong, Vikings quarterback also loses lustre

If only. Had Brett Favre three months ago ended his regular summer tease of the American media by announcing that he was finally retiring, once and for all, from the National Football League, then he would have left on a note that no 40-year-old practitioner of one of the most brutal sports on earth is ever likely to emulate.

True, he didn't quite lead the Minnesota Vikings last year to the Super Bowl they craved. But 2009 would have been among his finest seasons, even by the lofty standards of one of the greatest quarterbacks in history. Instead Favre decided on one more shot – and an astounding two-decade career seems destined to end in 2010 not in glory, but in a slough of on-field mediocrity deepened by off-field scandal. To put it bluntly, grandfathers shouldn't "sext".

This has not been a great 12 months for assorted colossi of American sport. First came the Tiger's disgrace, then the drug suspicions around Lance Armstrong – and now the possible unravelling of what surely will be the final season of one the most exciting, and certainly the most indestructible, quarterbacks ever.

"L'affaire Favre" erupted early this month when the website Deadspin posted a story featuring voicemails and lewd photos allegedly sent by the player to a hostess and in-house reporter for the New York Jets during the single season he spent with the team in 2008.

The messages include a man asking to meet with Jenn Sterger, the woman in question, who now works for the Versus television sports network. As for the pictures sent to Ms Sterger's cellphone, they feature a male sexual organ that may or may not belong to the Jets' then quarterback. Favre has refused to comment on the affair: "If you want to talk about what happened in the football game tonight, I'd love to," was all he would say after the first game since the news broke, in which the Vikings had lost to – of all people – the Jets.

Favre by his own admission has never been a saint, and he and Tiger Woods are far from the only superstars of American sport to be caught up in extra-marital scandal. Just ask Kobe Bryant of the LA Lakers, arguably the biggest global name in basketball, who a few years ago was at the centre of a sexual assault scandal. But Favre's fall from grace, if such it proves to be, has come at the most awkward of moments.

By the standards of such things, his alleged offence is relatively minor; indeed, Ms Sterger did not want the incidents to be made public and seems to have been "outed" by the website. Unfortunately, it coincides with a campaign by Roger Goodell, the NFL commissioner, to clean up the sport's raunchy, violent and sometimes lawless off-field image.

The Pittsburgh Steelers quarterback Ben Roethlisberger might have won a couple of Super Bowls before he was 27 – but that didn't spare him from being handed a six-game suspension by Goodell for the alleged sexual assault of a 20-year-old college student, even though charges were never brought.

Today Favre is due to meet National Football League officials to discuss the 'sexting' allegations. If they are shown to be true, then he could face a similar punishment, as well as an even more painful financial hit. His prowess on the field, coupled with good ol' boy charm and grizzled designer stubble, have made him a perfect pitchman for Wrangler jeans and Remington hunting rifles, among others. If the misconduct charges stick, sponsorship deals worth $75m (£47m) could disappear.

The scandal, however, is far from the only thing on his mind. "I'm concerned about the next game," was all he would say on Sunday, as reporters again tried unsuccessfully to elicit a comment on his reputed indiscretions. And well Favre might be concerned.

True, the Vikings had just scratched out a gritty 24-21 victory over the Dallas Cowboys. But it owed little to Favre, who, in another unconvincing display, threw for 118 yards and just one touchdown, and was repeatedly hit hard and sacked.

One reason for the indifferent performances is injury – no surprise for a player who turned 41 a few days ago, and since April has been a grandfather. In recent years Favre has suffered both shoulder and ankle trouble, and he described the elbow pain he experienced in the Jets game as the worst of a season only one-third over.

He was doubtful for the Cowboys game, and may remain so for the Vikings' highly charged encounter this weekend with their great rivals the Green Bay Packers – the team where Favre spent 16 seasons between 1992 and 2007, and won his lone Super Bowl in 1997. The odds are he will play, making what would be his 291st consecutive NFL start; his hickory-tough image is a large part of his appeal. But even if he does, Favre's personal problems may, Woods-like, already be affecting his on-field performance.

No scandal can take away Favre's achievements, as a three-times NFL most valuable player, and holder of a clutch of records, including yards thrown, completions and touchdown passes. Like the consecutive starts streak, they may never be matched. Only a fool would write Brett Favre off. But it is hard to see how this season will not be his last. And how much better, he must be thinking, had he never embarked upon it at all.

Favre's figures... and how his record compares with other us greats

* Minnesota Vikings' Brett Favre looks set to play his 291st consecutive game in the NFL on Sunday when he will face his former side Green Bay Packers – it is an ongoing record for a quarterback.

The former New York Jet has enjoyed a glorious career – winning the MVP award three times (1995, 1996 and 1997) and led the Packers to a Super Bowl title in 1997. The 41-year-old is the only quarterback in NFL history to have led his team to victory against all 32 teams since the League was expanded in 2002 and holds umpteen passing marks.

* Here's how his record compares with consecutive appearances in other sports:

Cal Ripken Jnr

The shortstop unsurprisingly acquired the nickname "Iron Man" after he played a mammoth 2,632 successive games for Major League Baseball side Baltimore Orioles between 30 May 1982 and 19 September 1998.

A C Green

Played in 1,192 NBA games in a row, appearing for the LA Lakers, Phoenix Suns, Dallas Mavericks, Toronto Raptures and Miami Heat from 1986 to 2001 – the power forward/centre only missed three matches in his career.

Brad Friedel

The ever-present American has played a Premier League record 236 games in succession, starting his run with Blackburn Rovers in August 2004 and now continuing it at Aston Villa.