McMahon, the ex-Chicago Bears star, has been outspoken on the issue and believes the league went so far as to conceal information related to concussions.
"We knew what was going on with pretty much every other part of the body," McMahon said on ESPN's Outside the Lines, per ProFootballTalk.com. "We knew there was going to be a chance for injury. But we didn't know about the head trauma. And they did, and that's the whole reason for this lawsuit. ... They knew about it and they didn't tell us. That's like looking in your face and lying to you. Flat-out lying.
"Short-term memory is not good," McMahon said. "I won't remember a hell of a lot about this interview in 10 minutes."
McMahon is part of at least four concussion-related lawsuits that have been consolidated in Philadelphia. The league has vowed to vigorously defend itself.
In a separate class-action lawsuit filed in February in federal court in New Orleans, several former Saints, including John Fourcade, are among 11 ex-players named as plaintiffs. The lawsuit says each of them has developed mental or physical problems from concussions or concussion-like symptoms.
A 2000 survey of more than 1,000 former NFL players found that more than 60 percent had suffered at least one concussion, while 26 percent had suffered three or more during their careers, according to the February lawsuit.