plaintiff's lawyers are going to have a hell of a lot better scientific case than they had with breast implants. I honestly think it will take an act of Congress to keep the NFL alive, giving them some sort of liability exemption similar to what ski resorts got years ago.
And don't think the NFL does not know this. If you are wondering why they handed out insanely over-the-top penalties for bounty-gate in New Orleans, this is why. They are working to establish a paper trail of extreme diligence on player safety issues for future litigation.