The 35-year-old offensive lineman lost 12 pounds in the past month while serving a four-game suspension for violating the NFL's policy on performance-enhancing substances. He said he took an over-the-counter diuretic, one that's banned because it can mask steroid use.
"Poor judgment," Williams said. "No one to blame but myself. The first thing I said was I was going to turn this from a negative into a positive, and I have. I've been in the best shape since entering the league. I'm as light as I've ever been, quicker."
The Bengals (2-2) are thrilled that he's back, even if there's a little less of him. He's likely to start Sunday in Jacksonville (1-3), balancing a running game that has definitely tilted left without him.
Cincinnati started rookie Clint Boling at right guard in the first three games. He struggled early in a third-game loss to San Francisco and was replaced by Mike McGlynn, who started a 23-20 win over Buffalo on Sunday. With Williams out, the Bengals' running game usually went the other way.
The Bengals have run 33 plays behind left tackle Andrew Whitworth, the most in the league. It's the same number of plays that they've run behind the right guard and tackle combined. Whitworth is their best lineman, but the Bengals would like some balance in running the ball.
They ran the ball to the right side better when Williams played in the preseason.
"We had some fun over there," Williams said. "Planning on getting back to those days."
The Bengals received a one-week roster exemption for Williams. Coach Marvin Lewis said he'll decide whether to add him to the roster later in the week. Given that he has stayed in good shape, Williams is likely to be activated and start.
"He used his time to benefit himself both physically and mentally," Lewis said.
Whitworth hugged Williams when he saw him in the locker room, welcoming back a player that the rest of the line calls "Boss." Williams is in his eighth season with the Bengals, the most experienced veteran on the line.
"He's inspirational for guys to play with and to see in the huddle and feel more confident," Whitworth said. "When you are dealing with young football players, I think it is important for them to feel confidence in the huddle. And he is another guy that provides a lot of confidence."
Williams is known for his durability. He had missed only three games in the last seven years -- all in 2006, when he had an appendectomy and returned. Missing those first four games were tough.
"My wife said I picked up a second addiction besides eating -- well, lack of now -- and that's hitting the gym," Williams said. "I took to it hard so I can come back. I was doing about three-hour sessions about five days a week, making sure my time was occupied."