Four former National Football League players, including two Pro Bowl players, sued the league over brain injuries that they say left them facing medical problems years after their careers ended.
Dorsey Levens and Jamal Lewis, both named to the annual All-Star Pro Bowl, as well as Fulton Kuykendall and Ryan Stewart, filed the lawsuit against the National Football League and NFL Properties LLC on Wednesday in U.S. District Court in Atlanta.
The suits are the latest in a series filed against the NFL in recent months by former players who say the league did not do enough to protect them from concussions.
The Atlanta suit alleges the NFL knew as early as the 1920s of the potential for concussions but only made them public in 2010.
"The NFL not only failed to take effective action in an attempt to protect players from suffering, but failed to inform players of the true risks associated with concussions," the suit said.
The NFL's practice was "to return players who had suffered concussions to the very game in which the injury occurred."
In response, the league said it had long made player safety a priority and continued to do so.
"Any allegation that the NFL intentionally sought to mislead players has no merit," the NFL said in a statement on Thursday.
"It stands in contrast to the league's actions to better protect players and advance the science and medical understanding of the management and treatment of concussions."
The four ex-players live in the Atlanta area.
Kuykendall, 58, a former linebacker, played in the NFL between 1974 and 1985. Stewart, 38, was a safety for the Detroit Lions until his career ended in 2000.
The men said they had a number of medical problems arising from their playing days. They include memory loss, headaches and sleeplessness.
About 10 federal lawsuits have been filed against the NFL by former players and some have been merged into class actions. A panel of federal judges will meet on January 26 in Miami to decide whether to consolidate the lawsuits into a single case.