According to Dan Graziano of ESPN, the Browns have relieved Williams of his duties as defensive coordinator and interim head coach, and he's "no longer with the team."
That news follows the report by ESPN's Chris Mortensen that Freddie Kitchens will be named the team's next head coach Wednesday.
The Browns hired Williams to coach their defense in 2017 after he spent the previous three seasons with the Los Angeles Rams.
At the time of his hiring, head coach Hue Jackson praised Williams' reputation over the course of his career and ability to turn defenses around in a hurry.
"I need growth over there as fast as I can get it," Jackson told reporters. "I truly believe in his track record and what he has done. ... I have to do what I think is right to get us to where we need to be. I think Gregg is that guy."
After the Browns fired Jackson on Oct. 29, Williams took over on an interim basis. It was his first stint as a head coach since going 17-31 in three seasons with the Buffalo Bills from 2001 to 2003.
Williams went 5-3 in eight games leading the Browns. The last Cleveland head coach to post a winning record in his first season was Bud Carson in 1989.
That's good news for Williams, who should get the opportunity to interview for a full-time head coaching job elsewhere.
For Cleveland, this season was a rousing success. Baker Mayfield showed superstar potential as a rookie. Myles Garrett and Denzel Ward are franchise building blocks on defense.
Kitchens will have a lot of talent to work with as the Browns chase their first playoff berth since 2002.