Peterson sits out practice; Herrera listed as doubtful

Already suffering from an ankle injury, Vikings running back Adrian Peterson was listed as questionable for Sunday's game against Chicago after he missed Friday because of an illness.

Asked if Peterson's illness was cause for concern, coach Brad Childress said: "It's a concern today. He's sick, but that's it."

Peterson has rushed for 554 yards on 90 carries and has eight touchdowns in four games against the Bears. Chester Taylor, who had 73 yards rushing on 11 carries last Sunday against Seattle, stands to carry the rushing load if Peterson is limited or out.

The Vikings' injury concerns extend beyond the running back position.

Anthony Herrera, who has not missed a start since taking over at right guard in the fifth game of 2007, did not practice all week after suffering a concussion against the Seahawks and is listed as doubtful. Artis Hicks likely will start in Herrera's place. Hicks, who played right tackle in place of injured Phil Loadholt in Week 5 at St. Louis, ordinarily gets reps at both tackle and guard spots in practice but concentrated on guard this week.

"Any time you get reps at a spot naturally you feel comfortable because you're getting the quality looks that you need throughout the week," said Hicks, who played right guard in 2006 and early in 2007. "It definitely helps out."

Said offensive coordinator Darrell Bevell: "Artis has been our utility guy. We can put him in just about any spot, left side or right side. The only one he hasn't handled is center. He's invaluable to our team."

Cornerback Antoine Winfield, who has missed the past four games because of an injured right foot, was limited in practice all week but hopes to return. He said he didn't have any setbacks this week but wants to test the foot before Sunday's game. He is listed as questionable.

"I think I'll be full go," he said. "I wouldn't want to get out there and make excuses. If I'm not 100 percent, I won't be out there."

Winfield said he can run forward and backward with no problem, but the issue is his ability to push off after he plants. "Every time you try to plant and go, I feel it right there," he said. "Once that starts to calm down I'll be good."

Receiver Bernard Berrian (hamstring), linebacker E.J. Henderson (knee), cornerback Benny Sapp (groin) and fullback Naufahu Tahi (ankle) are all probable.

Bevell said he considers a completion percentage ranging from 60 to 65 percent in the West Coast offense a "really good" game for a quarterback. Brett Favre has completed 69.7 percent of his passes, including a career-high 88 percent against Seattle last week.

Favre's three interceptions is the lowest total among quarterbacks with at least 200 attempts and easily his career low after 10 games. He threw seven interceptions through 10 games in 2002.

"You probably say it's amazing for a guy with his past, but I think that's a great year for any of the quarterbacks, whether it's [Peyton] Manning or [Tom] Brady or any of those guys," Bevell said. "That's a great season that he's putting together so far.

"Obviously everyone is going to point to how well he's taking care of the ball, which obviously that's easy to point to. But he's throwing the ball very accurately. He's going through his progressions well. He's getting everyone involved. The immeasurable part is the leadership skills that he brings to us. Everyone rallies around him and he picks everyone up."

• Vikings defensive tackle Jimmy Kennedy was fined $5,000 for a major facemask penalty last week. Seattle's Jordan Babineaux also got a $5,000 fine for his major facemask penalty against Percy Harvin.

• The Bears listed tight end Desmond Clark (neck) as doubtful.