EDEN PRAIRIE, Minn. -- Down to the last few days of the season and maybe Brett Favre's career, the NFL ended a slow-paced investigation of tawdry allegations against the quarterback with a $50,000 fine and a rebuke for not being candid.

The league punished one of its marquee players for failing to cooperate with investigators who were trying to determine if the 41-year-old quarterback sent inappropriate messages and below-the-belt photos to Jenn Sterger in 2008, when both worked for the New York Jets.

The ruling came days before what could be the final game for the three-time MVP. He'll start for Minnesota at Detroit on Sunday if he's recovered from a concussion sustained Dec. 20 against Chicago, and has said this will be his final season, though he's unretired in the past. He made the declaration even before his NFL record for consecutive starts was snapped at 297 in mid-December.

It's been a tough season on the field for Favre and his Vikings, and by the league's own admission, the investigation begun in early October has generated plenty of bad publicity for all the parties involved -- Favre, Sterger and the NFL itself.

Yet commissioner Roger Goodell "could not conclude" that Favre violated the league's personal conduct policy based on the evidence currently available to him, the league said in a statement announcing the fine.

Forensic analysis failed to establish that Favre sent the objectionable photographs to Sterger, the league said.

Favre's punishment stems from Goodell's determination that he was "not candid in several respects during the investigation resulting in a longer review and additional negative public attention for Favre, Sterger and the NFL," the league said. The commissioner also told Favre that if he had found a violation of the league's workplace conduct policies, he would have imposed a "substantially higher level of discipline."

The NFL said its sole focus was on whether Favre violated workplace conduct policy, not to "make judgments about the appropriateness of personal relationships."

There was no comment from Favre and his agent, Bus Cook, did not return messages.

The ruling drew a swift and bitter response from Sterger's attorney, who accused the league of favoritism.