ORCHARD PARK, N.Y. -- High-priced defensive end Mario Williams is feeling the heat more than he's been applying it four games into his first season with the Buffalo Bills.
And Williams complained on Wednesday that a sore left wrist that's bothered him since the start of the season isn't helping.
"It's just lingering a little longer than I expected, and I just have to get back out there and try to deal with it and play better with it," Williams said, referring to an injury he sustained in the final week of the preseason.
As for his production, 1 1/2 sacks, 11 tackles and a fumble recovery, Williams acknowledged he has to do better.
"I just got to have more impact, more of a role in things and get back to like I used to play," he said.
The two-time Pro Bowl selection and feared pass-rusher isn't anywhere near the dominating form he had during his six seasons in Houston, where he set a franchise record with 53 sacks. That was the kind of production the Bills were counting on in March, when they made Williams the NFL's most expensive defensive player by signing him to a six-year, $100 million contract.
His arrival was regarded as a turning point for a small-market team making a serious commitment to retool a porous defence in a bid to end a 12-season playoff drought.
Four games in, the Bills (2-2) are preparing to play at San Francisco (3-1) with a defence that's been inconsistent at best. It's coming off a monumental collapse in a 52-28 loss to New England, a game in which Buffalo surrendered 580 yards of offence -- the second most in franchise history -- and allowed the Patriots to score touchdowns on six consecutive drives during a 45-point second half.
Williams was limited to two tackles on Sunday, and singled out by critics for the second time this season.
"If Mario Williams doesn't start picking it up, there are going to be a lot of 2013 free agents who suffer because so far, Williams has been an argument against spending big money," said Dan Pompei of the Chicago Tribune in submitting his vote in the AP Pro32 rankings this week.
Williams had been previously criticized by NFL safety-turned-broadcaster Rodney Harrison after failing to make a dent in a 48-28 season-opening loss at the New York Jets.
Saying he tunes out outside criticism, Williams is instead motivated internally.
"I feel my pressure, man," Williams said. "I mean, I know what's here and I know what I need to do."
Williams' presence has helped a defence that already has 10 sacks -- six more than Buffalo had through four games last year. Inconsistency, however, has been a problem.
In two wins, the defence has surrendered only 31 points, 662 yards and had nine sacks and five turnovers. In two losses, Buffalo's allowed 100 points and 964 yards, while managing just one sack and forced three turnovers.
Bills coach Chan Gailey had a mixed response when asked of Williams' production.
Gailey began by saying Williams is "trying to play the best he can play."
That doesn't mean there isn't room for improvement.
"Can he play better? Yeah, he can play better. But there's a lot of guys that fall into that category," Gailey said, including himself as a coach. "Does everybody wish his numbers were up? Yeah."
Gailey also couldn't assess how much the wrist injury is bothering Williams, but noted the injury hasn't been severe enough to have the player listed on the team's injury report.
It's unclear when Williams was hurt, though he was first spotted having his hand wrapped in practice on Labor Day.
Williams said he was hurt during a "freak" occurrence, and added the injury has affected his pass-rushing ability because he uses his hands in trying to beat blockers.
"It's just been a little odd just having a little knick or whatever, and not being able to use it to the full extent," Williams said. "But you know, you got to play. ... If you're out there on the field, you've got to make it happen."
NOTES: S Jairus Byrd (hip) missed practice Wednesday, but is expected to return Thursday, while DT Spencer Johnson did not practice due to an ankle injury. ... LT Cordy Glenn and RG Kraig Urbik are both expected to be out after hurting their right ankles last weekend. ... The Bills signed OL Reggie Stephens to their practice squad and released WR Kamar Aiken. Stephens, a 2010 seventh-round draft pick by Cincinnati, spent his rookie season with the Bengals.