Four questions about the Vikings and Bears

As the Vikings head into Sunday's game against the Bears, here are four questions we're trying to answer.1 What can we expect out of second-year cornerback Chris Cook?

Antoine Winfield missed practice again Friday and is listed as doubtful for Sunday. Winfield hasn't practiced since Sept. 30, continuing to recover from neck stiffness.

That's left Cook to assume a heightened role. And last week, he was up to the challenge, continuing to emerge as a difference-maker in coverage. In recent weeks, Cook has shown promising moments against both Calvin Johnson and Larry Fitzgerald, success that brings an obvious psychological boost.

"His confidence has really grown," coach Leslie Frazier said. "He's a big, fast, physical guy who has become a much better tackler as well -- which is a complement to his cover skills. We knew he could cover, but he's tackling better. And that's what we need in our scheme."

If Winfield's out, Cook will start opposite Cedric Griffin and will head into the game with far more momentum than Bears receivers Johnny Knox, Devin Hester and Roy Williams.

Said Cook: "Right now, my confidence is at an all-time high. And I think it's only going to go up."

2 Just how vulnerable is the Bears defense these days?

As if that wasn't bad enough, they're now reshuffling their lineup, too. In the secondary, safeties Chris Harris and Brandon Meriweather are being pulled from the starting lineup, replaced by Chris Conte and Major Wright.

And adding injury to insult, defensive end Julius Peppers might be limited at best Sunday night if he plays at all. Peppers sprained the medial collateral ligament in his left knee Monday night and hasn't practiced all week.

The Bears rank 21st in the league in sacks with nine, a half-sack ahead of Jared Allen's individual total. Translation: If Donovan McNabb can't get into a rhythm Sunday, hope for his resurgence might be totally shot.

3 Are there any offensive surprises up the Vikings' sleeve this week?

It's not so much a surprise as it is a renewed effort to get Lorenzo Booker involved. Booker had two catches for 25 yards and added a 25-yard run in last week's victory over Arizona.

Booker continues to impress the coaching staff not just with his speed but with his overall instincts. He's reliable in pass protection, a dangerous receiver and should be in line to see more action as a ball carrier.

It's also worth noting that Vikings receiver Percy Harvin returned to practice Friday after being held out Thursday because of sore ribs. Harvin is listed as questionable for Sunday but should be ready.

4 What is the biggest key for the Vikings defense this week?

So much talk has centered around the Bears' shaky offensive line and the potential for Vikings ends Jared Allen and Brian Robison to have a field day. But task No. 1 for the Vikings will be containing Bears back Matt Forte.

Forte has touched the ball on 112 of the Bears' 294 offensive plays this season and leads NFL running backs in yards from scrimmage (785). His 5.4-yards-per-carry average ranks fourth in the league among backs with at least 30 attempts. Forte also has 30 catches, second most of any NFL back.