NFL Network's Ian Rapoport passed along the statement from the Redskins, who are requesting the records under terms of the NFL's collective bargaining agreement:
Speaking to reporters Thursday, Williams said he "almost lost my life" due to a cancerous tumor attached to his skull that he had removed.
Williams noted it was first discovered six years ago, but team doctors told him it was a minor issue, "so I didn't really question it."
The 31-year-old reported to the Redskins this week, ending his holdout that began back in the summer when he skipped mandatory organized team activities. The team announced Thursday he failed his physical due to helmet discomfort, leaving his playing status in doubt.
Originally drafted No. 4 overall in 2010, Williams has spent his entire NFL career in Washington. The seven-time Pro Bowler is set to earn $12.5 million next season in the final year of his contract.