More than 100 former National Football League players have filed suit against the league.
They say NFL officials knew how dangerous hard hits and concussions are and hid that information.
The filing of this latest suit comes a day after former linebacker, Junior Seau, shot himself in the chest.
His death has been ruled a suicide, and many believe it might be related to a degenerative disease called CTE.
It comes from repeated blows to the head, but can only be diagnosed after death.
An attorney for some of the players in the lawsuit wants the NFL to prove safety is number one by setting up a medical monitoring system.
According to the lawsuit against the NFL, 12 cases of the CTE disease have been detected in dead players.