ORCHARD PARK, N.Y. -- Kyle Williams has taken the next big step forward on a surgically repaired left foot.

The Buffalo Bills defensive tackle has been cleared to practice on a limited basis.

"Yeah, it's good to be back even for just a few plays here and there," Williams said Tuesday after taking part in about half of the full-team sessions with his fellow starters in the second week of voluntary practices. "Just getting my foot in the door. And hopefully, when we get to training camp, I can be full bore."

Williams' recovery is a little bit ahead of schedule after being cleared for practice last week by both team doctors and specialist Robert Anderson. It was Anderson who performed the operation in November to remove bone spurs that were tearing at the player's Achilles tendon.

After participating in only individual drills during the first voluntary minicamp practice last week, Williams said he took part in only a snap or two per team session on Thursday and Friday.

Coach Chan Gailey said he's taking an extremely cautious approach in easing Williams back into practice.

Though he's experiencing some soreness, Williams said that was to be expected as part of the recovery process. The best part is that he no longer has to drill a big hole in the back of his left cleat, as he did last year, to relieve the pressure of the injury that had been nagging him for much of his six-year NFL career.

A starter since his rookie season, Williams was a 2010 Pro Bowl selection and the team's most consistent defensive lineman. He had also proven durable, having missed just two games before last season, when Williams lasted just five games and sat out three more before electing to have season-ending surgery.

Williams is being counted on to anchor a revamped defensive line that features new pass-rushing specialist defensive end Mario Williams, who was signed in free agency in March. It's also a unit that should include defensive end Shawne Merriman, who returned to practice last week after having season-ending surgery in November to repair a partially torn right Achilles tendon.

Gailey is impressed by what he's seen so far from Merriman, the three-time Pro Bowl selection who has been limited to playing in just eight games over the past two seasons because of the injury.

"He looks quick to me. He's coming off the edge with that same speed and quickness that I remember," Gailey said, of the NFL's 2005 Defensive Rookie of the Year. "The best thing about it is that he says he feels good. It's not one of those where he's feeling something or trying to hide something."

In other injury news, Gailey said backup quarterback Tyler Thigpen will miss at least this week of practice because of an abdominal strain. Gailey believes Thigpen should return next week.

Thigpen is competing with newly acquired free agent Vince Young for the No. 2 job behind starter Ryan Fitzpatrick.

Right tackle Erik Pears will be out until training camp next month after having minor surgery, Gailey said, without specifying what was repaired.

The Bills have two more voluntary practices this week, and four next week before opening a three-day mandatory minicamp on June 19.