Washington announced the roster move Thursday afternoon. NFL Network's Ian Rapoport added Williams' 2019 season is officially over, and the Redskins don't have to pay the rest of his salary this season (roughly $6 million).
Per Mark Maske of the Washington Post, Williams could go through the NFL Players Association to challenge Washington if it decides not to pay his salary.
Williams ended his holdout by reporting to the Redskins on Oct. 29, but JP Finlay of NBC Sports Washington reported the seven-time Pro Bowler had "no intention" of playing in 2019.
Finlay added Williams failed his team physical because of discomfort with his helmet.
Speaking to reporters for the first time on Oct. 31, Williams said he had a cancerous tumor removed from his skull that he was initially told about during the 2013 season by Redskins doctors, who downplayed the issue:
"I guess somebody took the time to actually try to see what was really going on there. 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 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 telling me I'm fine, then I'm fine. That's how I looked at it."
Following those comments, Washington issued a statement requesting the NFL's management council convene a joint committee with the NFLPA to review Williams' medical records and medical care.
Williams, 31, has spent his entire NFL career with the Redskins since being drafted No. 4 overall in 2010 out of Oklahoma. His last appearance came against the Philadelphia Eagles on Dec. 30, 2018.