Trent Williams walks off the field during a game against the Philadelphia Eagles on December 26, 2015 at Lincoln Financial Field in Philadelphia.
CNN  — 

Pro Bowl tackle Trent Williams, who ended his holdout with the Washington Redskins earlier this week, says he had a cancerous growth on his scalp and his team didn’t do anything about it.

“It was cancer,” Williams said Thursday. “I had cancer. I had a tumor removed from my skull, attached to my skull. It got pretty serious for a second. I was told some scary things from the doctor. It was definitely nothing to play with, one of the things that changed my outlook on life.”

According to ESPN, Williams, who spoke to reporters gathered at his locker, said he was diagnosed with a form of cancer called dermatofibrosarcoma protuberans (DFSP). Per the report, Williams did not name any of the team’s medical staff he believes is responsible. He also would not say if he would ever play for the team again this season.

Williams was asked by a reporter about when he first approached the Washington team doctor about this: “Probably like six years ago,” he said.

“I guess nobody took the time to actually realize, try to see what was really going on there,” Williams said. “Football was more important, and I mean, to me it was more important, too. I was told it was something minor, so I didn’t really question it. But, I mean, the lump continued to grow over the years. It was concerning, but there was no pain involved. If I’m being told by the very people who I put my career in the hands of, they’re telling me that I’m fine, then I’m fine. That’s how I looked at it.”

According to ESPN, Williams said team doctors did not tell him to see a specialist until this offseason. He had surgery in the winter, and Williams said, according to the ESPN story, he needed 350 stitches and 75 staples on his head and that the incision was about the size of a softball.

“We literally caught it within weeks of metastasizing through to my brain, to my skull,” Williams said, per the ESPN story. “Extracting it was the only thing they could do. Doing radiology on it would have put a cap on my life. I think 15 years was the most I would have had after I started chemo. So I had to cut it out.”

According to the ESPN story, Williams failed his physical on Tuesday because wearing a helmet causes discomfort on his scalp, which remains sensitive from the surgery.

The ESPN story says that Williams said he held out starting in June because he was upset with the medical staff, in addition to the team not giving him more guaranteed money in the final two years of his contract.

Despite speculation that he might be dealt, the team did not trade Williams by Tuesday’s 4 p.m. trade deadline.

In a statement Thursday, the team said it has “requested that the NFL’s Management Council convene a joint committee with the NFLPA to review the medical records and the medical care given to Trent Williams.

“We have requested this review under the NFL’s Collective Bargaining Agreement that provides for an independent third party review of any NFL player’s medical care. The Redskins continue to prioritize the health and well-being of our players and staff. Due to healthcare and privacy regulations, we are unable to comment further at this time. We look forward to the joint committee’s results.”