NEW YORK (Reuters) - Minnesota Vikings quarterback Brett Favre, who played the game with a boyish joy and bulldog determination, filed his retirement papers with the NFL after a 20-season career, the league confirmed on Monday.

The 41-year-old Favre, one of the game's most decorated players, sat out the final game of the regular season with a concussion and said it would be his last.

It is the third time Favre has retired from the NFL, but after failing to make the playoffs in a season that included tendinitis in his right elbow, a broken ankle and split chin, the gray-haired grandfather said this time was for real.

"I know it's time. And that's OK. It is," Favre said after the Vikings lost their final game of the season to the Detroit Lions on January 2. "I hold no regrets, and I can't think of too many players off hand that can walk away and say that."

Favre, who also said he understood that some fans would be skeptical of his decision being truly final, filed retirement papers with the NFL on Monday, the league told Reuters.

Favre, whose record streak of 297 regular season starts ended in December because of a sprained shoulder, was a shadow of the player who enjoyed so much success a year earlier when he led Minnesota to within one win of a Super Bowl appearance.

His reputation took a hit when he was fined $50,000 by the NFL in December for not cooperating with an investigation into allegations he sent lewd messages to a female employee of the New York Jets when he was with the club in 2008.

Favre is a three time winner of the NFL's most valuable player award and holds most major records for a quarterback, including career touchdowns, passing yards and wins.

He won a Super Bowl with the Green Bay Packers in 1997 and was selected for the Pro Bowl on 11 occasions.

Favre began his professional career in 1991 when he was drafted by the Atlanta Falcons but did not make a great start. His first NFL pass was intercepted for a touchdown and he was traded to the Packers the following season.

In 2008, Favre retired for the first time. But a few months later he signed with the New York Jets. He retired again after one season with the Jets but made another comeback, this time for the Vikings.

Despite his advancing years, Favre had one of the best statistical seasons of his career in 2009, throwing for over 4,200 yards, 33 touchdowns and only seven interceptions.

But Favre's number dropped off in his final season as he threw for 2509 yards and 11 touchdowns, the lowest totals since his rookie year when he played two games.

The Vikings, who began the season with hopes of making another playoff run, finished last in the NFC North Division with a 6-10 record.

Favre watched his final NFL game from the sidelines given post-concussion symptoms after being slammed to the turf during a game against the Chicago Bears two weeks earlier.

(Reporting by Julian Linden; Editing by Frank Pingue)