ATLANTA -- Jamal Lewis, Dorsey Levens and two other former NFL players say in a federal lawsuit that brain injuries have left them struggling with medical problems years after their playing days ended.

Lewis and Levens, along with Fulton Kuykendall and Ryan Stewart, filed the lawsuit against the National Football League and FNL Properties LLC this week in U.S. District Court in Atlanta.

Lewis, 32, rushed for 10,607 yards in nine seasons (2000-09) with the Baltimore Ravens and Cleveland Browns. His 2,066 yards rushing in 2003 rank behind only Eric Dickerson's 2,105 in 1984 all-time among single-season rushing totals.

Levens, 41, rushed for 4,955 yards in 11 seasons (1994-2004) with the Green Bay Packers, New York Giants and Philadelphia Eagles.

Kuykendall, 58, played 11 NFL seasons (1975-85) as a linebacker for the Atlanta Falcons and San Francisco 49ers.

The 38-year-old Stewart, who co-hosts the "2 Live Stews" radio show in Atlanta with his brother Doug, is a regular contributor on the "ESPN First Take" debate desk. He played five seasons (1996-2000) as a defensive back for the Detroit Lions.

All four ex-players live in the Atlanta area.

The players maintain the NFL knew as early as the 1920s of the potential for concussions to harm its players. The men claim a range of medical problems stemming from their playing days, including memory loss, headaches and sleeplessness. They are seeking a jury trial and unspecified damages.

"The NFL has done everything in its power to hide the issue and mislead players concerning the risks associated with concussions," the players argue in the lawsuit.

The NFL responded that it has long made player safety a priority and continues to do so.