The NFL and the NFL Players Association will investigate and evaluate the medical care the Washington Redskins gave star left tackle Trent Williams, a league spokesman said Friday.

Under the terms of the collective bargaining agreement, medical experts appointed by the league and the players’ union will conduct the investigation. The Redskins could be subject to discipline by the NFL — probably a fine — if they are found to have committed wrongdoing.

“The NFL and NFLPA will conduct a joint investigation into the claims made by Trent Williams as provided for in the CBA,” NFL spokesman Brian McCarthy said. The league and union declined to comment on the details of the case.

Williams said Thursday that doctors for the Redskins failed to recognize in a timely manner that a growth on his head was cancerous. Williams said he was suffering from Dermatofibrosarcoma Protuberans, a soft tissue sarcoma that develops in the deep layers of the skin.

He noticed the growth during the 2013 season and asked the medical staff about it then and at other times later, Williams said, but he was told he had nothing to worry about. Williams said the team grew concerned this past offseason and sent him to a team-affiliated hospital. Williams said he ultimately was diagnosed with a cancerous tumor and had surgery to have it removed.

Williams said Thursday he “almost lost my life” and was told by a doctor to get his affairs in order.

“We literally caught it within weeks of metastasizing through to my brain to my skull,” said Williams, who spoke to reporters for close to 20 minutes Thursday. “I guess nobody took the time to see what was going on there. Football was more important, and to me it was more important, too. I was told it was something minor, so I didn’t really question [the team doctors].”

The Redskins said in a statement Thursday that they requested a joint review by the NFL and NFLPA.

Williams’s case will be reviewed by a panel of three doctors unaffiliated with the league or union. The league will choose one of them. The union will choose another, and those two doctors will select the third. If given Williams’s permission, they will review the Redskins’ medical records and the records of his second opinion. Those doctors will produce a report that will be reviewed by the NFL and NFLPA.

Williams, a seven-time Pro Bowl selection, reported to the team Tuesday, ending his season-long holdout. Interim coach Bill Callahan said Wednesday that Williams failed his physical because he experienced discomfort when he put on a helmet. He cannot practice or play for the Redskins until he passes a physical, and the team was given a two-week roster exemption.

If he’s unable to pass a physical by the time the exemption expires, the Redskins must make a roster move, perhaps placing him on the non-football injury list. Williams declined to say Thursday whether he will play for the Redskins again and smiled when asked whether he wants to be traded. His contract with the Redskins runs through the 2020 season.

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