Even as the Minnesota Vikings enter Week 7 at 5-0, there's no mystery about the biggest vulnerability of the NFL's lone undefeated team.

An overextended offensive line with both starting offensive tackles on injured reserve could be costly for a team that has weathered a series of early season blows. Now the unit will have to find a way to stand up to the Philadelphia Eagles' formidable front four to keep quarterback Sam Bradford protected against his former team on Sunday.

A bye week gave Vikings coach Mike Zimmer time to retool, and the team added veteran offensive tackle Jake Long. But Minnesota will have to find a way to stand up to an Eagles defense that can generate pressure with its front four alone.

Eagles coach Doug Pederson and defensive coordinator Jim Schwartz will demand more from their line after it gave up 230 rushing yards and struggled to pressure Kirk Cousins in a 27-20 loss to the Washington Redskins last week. Defensive tackle Fletcher Cox is looking to recapture the disruptive form that earned him NFC defensive player of the month honors in September.

With Philadelphia relying on its pass rush to provide a spark, the Vikings will be counting on Bradford to keep his cool. He hasn't thrown an interception in 125 pass attempts this year, and the offense has yet to commit a turnover.

Philadelphia has its own concerns up front on offense. Right tackle Halapoulivaati Vaitai was overwhelmed in his first start last week against the Redskins, and the Eagles allowed Carson Wentz to be sacked five teams. Those woes could spell trouble against a Vikings defense tied for third in sacks with 19.

Here are four other matchups that will define Week 7 in the NFL:

Steelers RB Le'Veon Bell vs. New England Patriots linebackers

Patriots coach Bill Belichick raved about the Steelers' all-purpose threat this week, and it's clear he won't be losing track of him on Sunday. With quarterback Ben Roethlisberger sidelined after knee surgery, a balanced outing from Bell is Pittsburgh's best hope for toppling New England on Sunday.

Controlling the clock with Bell and DeAngelo Williams could be important, as limiting Tom Brady's opportunities will aid a defense that ranks 30th against the pass. But Bell's biggest contributions might be in keeping Pittsburgh's own aerial attack running. Landry Jones has been shaky when filling in for Big Ben before, and Bell is an adept pass catcher both out of the backfield and split out wide.

Beyond building a big lead and forcing the Steelers to play catch up, the Patriots' best route for rattling Jones is to neutralize Bell. Linebacker Jamie Collins is questionable to play with a hip injury, but his versatility and coverage skills could serve as a critical counter to Bell. Dont'a Hightower was named AFC defensive player of the week for Week 6 and is the strongest asset for stopping Bell in the run game.

Cardinals RB David Johnson vs. Seahawks' front seven

Johnson is enjoying the breakout season many expected from him, as the second-year running back leads the NFL in yards from scrimmage with 833. Moreover, he has helped ease the offensive transition to a more methodical attack from last year's quick-strike approach.

In the past two weeks, Johnson has rushed for 268 yards and five touchdowns on 49 carries. A patient running style and impressive acceleration combine to make him one of the NFL's most dangerous big-play threats.

Seattle's primary focus will be containing Johnson and forcing the offensive burden on Cardinals quarterback Carson Palmer, who is recovering from a hamstring strain. The Seahawks have kept opposing backs in check and rank third in rushing defense with just 74.6 yards allowed per game. Johnson also is a standout in the passing game, but Seahawks linebacker K.J. Wright is one of the NFL's best at his position in coverage.

Falcons offensive line vs. Chargers pass rushers Joey Bosa, Melvin Ingram

Matt Ryan's mid-career renaissance can be attributed in part to an improved offensive line. With better protection than in previous years, Ryan has capitalized on opportunities throwing the ball down the field. Ryan has completed 14 of 24 attempts on passes 20 or more yards down the field, according to ESPN, netting a total of 566 yards with five touchdowns and no interceptions on those throws.

Jake Matthews and Ryan Schraeder's maturation have given Atlanta one of the NFL's best offensive tackle tandems. But cracks are starting to show for the top-ranked offense. The Seahawks sacked Ryan four times and landed 13 hits on him in last week's 26-24 win.

San Diego might need a similar output from its pass rush to cover for an injury-riddled defense. Bosa has been a disruptive force in his first two games despite sitting out the first month after a hamstring injury and prolonged contract negotiations delayed his debut. Ingram quietly has emerged as the kind of slippery pass rusher the Chargers envisioned when they made him a first-round pick in 2012.

Texans QB Brock Osweiler vs. Broncos' pass rush

In the lead-up to facing his former team, Osweiler has been diplomatic about his departure from Denver. But that approach won't earn him any leniency from an aggressive Broncos defense.

With a 59% completion rate and eight touchdowns against eight interceptions, Osweiler hasn't fulfilled the lofty visions many had for him and the Texans this year. He showed signs of progress last week in an overtime win over the Indianapolis Colts, but a strong performance Monday could serve as a springboard for the rest of the season.

Standing up to the Broncos' pressure will be the biggest test for Osweiler. Von Miller and Denver's defense, which has a league-best 21 sacks, could provide the same kind of pass rush that led Osweiler to unravel in a 31-13 loss to the Vikings two weeks ago. Denver's opportunistic secondary also looms as a danger for Osweiler, who has thrown at least one interception in every game so far this season.