The US National Football League cannot claim immunity from lawsuits brought by thousands of former players over concussions they say they sustained on the field, one of their lawyers has told a federal judge.
The league had established itself as the ''guarantor of player safety'' since the 1920s and could not now hide behind collective bargaining agreements to shirk its duty of care, David Frederick, a lawyer for former players, told US District Judge Anita Brody in Philadelphia federal court.
''When the NFL began to monetise and glorify violence on the field, it breached its duty of due care,'' Mr Frederick said. ''It can't claim immunity simply because clubs have a contractual relationship with a players union.''
The NFL is seeking to have the suits dismissed, saying the claims are a matter of workplace safety governed by contracts with the league's union and its 32 member clubs. Paul Clement, a lawyer for the NFL, said the players' association and the teams shared responsibility for player safety with the league.
''You can't think of the league's responsibility in a vacuum,'' Mr Clement said. ''The league can't unilaterally change rules without participation from the clubs, players and the union.''
More than 4000 former NFL players have sued the league seeking damages for head injuries. The complaints, which are consolidated in this case, accuse the league of negligence and failing to inform players of the link between repeated traumatic head impacts and long-term brain injuries.
The players claim the NFL knew as early as the 1970s about the increased risk of repetitive head injuries and allegedly took no substantial steps to deal with the issue until 1994. It later sought to suppress medical literature showing a link between head injuries and post-career brain damage.
Autopsies of Junior Seau (San Diego Chargers), Dave Duerson (Chicago Bears) and Andre Waters (Philadelphia Eagles) showed they suffered from a progressive brain disease known as chronic traumatic encephalopathy before committing suicide.
Their families are suing the NFL and Riddell Sports, the league's official helmet provider, for refusing to properly acknowledge or address the concussion threat.
''The NFL for decades had information about neurological risks, and because it didn't cause bleeding and cause broken bones, the league ignored it,'' Mr Frederick said.
Judge Brody, who is supervising the exchange of pretrial evidence in the case, will decide whether the players' claims can proceed to trial. She has not yet indicated when she would rule.