Trent Williams is frustrated with the Washington Redskins, in part because of a medical issue.

Williams underwent a procedure to remove a benign growth from his head this offseason. The tackle is upset over that and also wants to renegotiate his contract, according to sources.

His current contract expires after the 2020 season.

"Well, I know he's frustrated," Jay Gruden said. "Any time you have something done, a procedure like that, of that magnitude, you want to find the reason. You wish something, maybe, could've been done differently or different timing, but our doctors are very good. I know they did the best they can. I mean, they have plenty of degrees. I know they did the right thing in their mind, and I know Trent's probably frustrated.

"But at the end of the day, we want him back, staff wants him back, players want him back and hopefully we'll get it fixed."