EDEN PRAIRIE, Minn. -- Antoine Winfield, the Minnesota Vikings' smallest player, left a giant hole in the defense when he left last weekend's game against the Baltimore Ravens with a sprained right foot.

The Vikings are hoping the 5-foot-9, 180-pound Pro Bowl cornerback can be ready for a big test Sunday in Pittsburgh against the suddenly pass-happy Steelers.

But Winfield has missed the first two days of practice this week, which isn't a good sign.

"If there's anybody that has a chance (to play) because of the notes he takes and how he looks at it, (it's Winfield)," Vikings coach Brad Childress said Thursday. "At some point, you have to warm up and move around, but I don't know right now."

The contrast between Minnesota's defense with Winfield and without was stark last Sunday. The Vikings forced the Ravens to punt on their first five possessions as they jumped out to a 14-0 lead. One of the NFL's best tackling cornerbacks held the edge against Baltimore's running backs and kept wide receivers Derrick Mason and Mark Clayton under wraps.

But Winfield went down during the second quarter, and Ravens quarterback Joe Flacco started to pick apart the Vikings' secondary.

"I don't think you can (compensate) for a guy like Antoine with some of the things he does," Vikings defensive tackle Kevin Williams said. "He's so physical. You very seldom see corners like that, who are that physical in the run game. He plays a big part when we're in our Cover 2 defense. Those guys know their role and they'll step up and help us out with that."

Flacco went right at backup Karl Paymah, who played almost exclusively on special teams in the first five games of the season. Paymah was beaten throughout the second half, particularly when Flacco threw for 196 yards and two touchdowns in a 21-point fourth quarter.

One of the most glaring plays was a 63-yard catch-and-run by Ravens running back Ray Rice to Winfield's side of the field.

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The Vikings held on for a 33-31 victory when Ravens kicker Steve Hauschka's 44-yard field-goal attempt sailed wide left at the final whistle.

"It was a tough position to put any corner in last week," Vikings linebacker Ben Leber said. "Backups get marginal reps during the week, and to ask these guys to come in and play at a high level is a tough thing to do. No doubt they have to do it. This is our first real test with (Winfield) not being in the lineup, so it still remains to be seen."

Childress said the Vikings will evaluate Winfield throughout the week, hoping to make a decision on his playing status by Sunday. But Leber wasn't the only player speaking as if they would be without one of their leaders against the physical Steelers offense.

"When one guy goes down, the next guy stands up," cornerback Cedric Griffin said. "We have talented guys here on our team. All of our guys just have to elevate and just replace Antoine."

The timing is difficult for the 6-0 Vikings, who are off to their best start since 2003.

The Steelers (4-2) have morphed from a power-running team into a wide-open, shotgun attack. Quarterback Ben Roethlisberger has attempted at least 30 passes in all six games this season, and he threw for 417 yards last weekend against the Cleveland Browns. Hines Ward leads the league in receiving, and fellow wide receiver Santonio Holmes and tight end Heath Miller give Pittsburgh a balanced aerial offense.

It remains to be seen what the Vikings will do if Winfield can't play. Paymah could make the start, or nickel back Benny Sapp might slide to the outside to take Winfield's place. Rookie cornerback Asher Allen, a third-round draft pick out of Georgia, is a candidate to be activated for the first time in his NFL career.

"We all have confidence in myself, Karl Paymah, Benny, Asher," Griffin said. "We'll get the job done."

Allen has been practicing both on the outside and covering the slot in Minnesota's nickel package.

"I played corner my whole career in college. I played in the SEC and went against talented receivers that are in the NFL now," Allen said. "Also played nickel. If coach wants to put me outside, he can do that. ... Just whatever's best for the team, I'll be doing it."