Kevin Williams is one of the NFL's elite defensive tackles. However, Monday night in Chicago his statistical line did not reflect the numbers of a potential Hall of Fame player.

Williams was credited with no tackles. In fact, his entire stats line was made up of zeroes. But Vikings defensive line coach Karl Dunbar said Friday that when he went back and reviewed film of the game he found Williams had three tackles and two assists.

Dunbar also said that no one should be overly concerned about Williams' performance of late, even though he hasn't had a sack since Nov. 15 against Detroit. Williams has six sacks on the season, tying him for the NFL lead among defensive tackles.

"He's doing everything we ask him to do," Dunbar said.

Dunbar said the issue is that Williams and defensive end Jared Allen -- both are Pro Bowl players -- are seeing numerous double teams from opponents and if nothing else they are being blocked by two guys on almost every play because teams are providing what is called chip help. Simply put, it means an opposing player will throw a quick block to help a teammate before heading on to the next assignment on a given play.

"[Williams] shows up and when you play inside and you're getting double- and triple-teamed, you're getting backs hitting you," Dunbar said. "If you can draw that much attention, somebody else needs to step up."

Williams said what is happening is a guard and tackle are often assigned to block him. "It's slowing us down but that's [the other team's] job," Williams said. "They are supposed to design something to slow us down and they've been doing a good job. We just have to find a way to fight through and not even pay attention to it."