MINNEAPOLIS -- An attorney for Korey Stringer's widow said she will sue the NFL on Monday, alleging that the league's policies led to Stringer's heat stroke death during Minnesota Vikings training camp in 2001.

Stan Chesley said Kelci Stringer's suit would also name football helmet maker Riddell Sports Group Inc., and some NFL medical advisers. He said the federal lawsuit would include a wrongful death claim on behalf of Stringer's widow and son, and a class action claim on behalf of all NFL players.

"What's on trial here is the rules and procedures and the culture" of the NFL, Chesley said Saturday. "Frankly, it's no coincidence that the average football player in the NFL plays for 4{ years. They use them up and spit them out."

Chesley declined to say publicly where the lawsuit would be filed. The planned suit was first reported by The New York Times.

Stringer collapsed during training camp on July 31, 2001, in sweltering heat and humidity. The 335-pound Pro Bowl lineman's body temperature was 108.8 degrees when he arrived at a hospital. He died 15 hours later.

Phone messages left by The Associated Press with an NFL spokesman and Riddell were not immediately returned.

Kelci Stringer had already filed a $100 million wrongful-death lawsuit against the Vikings and the team's training camp physician, David Knowles. In April, a Hennepin County District Court judge dismissed Kelci Stringer's claims against the team. She later settled with Knowles for an undisclosed sum.

Her attorneys said at the time they planned to ask the state appeals court to reinstate the claims against the Vikings.

Chesley said the issues in the new lawsuit are different. The suit against the team stumbled because the law limits how much Stringer's widow could get from his employer, the Vikings. Chesley said that while the league does not employ the players, it sets the procedures for the mandatory training camps.

Chesley said the league wanted a 335-pound player like Stringer but then did little to protect him in the heat that led to his death. He said the lawsuit is designed to change that.

The NFL has said it has already made changes.

Before training camp opened in 2002, the NFL consulted with several experts and held a series of discussions and seminars on the subject. The league banned the herbal stimulant ephedra and began random testing for it last summer after learning that dietary supplements increased the risk of heat-related illnesses.

A bottle of Ripped Fuel, which contains ephedra, was found in Stringer's locker after he died, though Stringer's remains weren't tested for the substance during investigations of his death.