So far this season, the Bears offense has been unlike any in today's NFL. Second-year quarterback Justin Fields has completed fewer passes than any quarterback to start a season in the last 40 years, and Chicago is running the ball 62.1% of the time. An NFL team hasn't finished a season with a run rate over 60% since the 2004 Steelers.

While that Pittsburgh team finished 15-1, it had the NFL's No. 1 defense and a running duo of Jerome Bettis and Duce Staley propping up a rookie quarterback named Ben Roethlisberger. The Bears don't have that kind of supporting cast for Fields. But Chicago does have the talent to test a Vikings run defense that hasn't exactly been lights out.

One focus at TCO Performance Center this week has been on the perimeter, where Vikings defenders are expecting to chase Bears runners in an offense that trails only the Eagles in how often they run to the edge — 11 times per game.

"We want to ensure great edges in our defense," nose tackle Harrison Phillips said. "That's something we're excited to work on this week, because we have a great test in front of us. They run the ball very well. It's always a fun feeling to get back out there and put our stamp of our standard on the field."

The Vikings defense needs to sharpen its edges after they were caught out of place at times during last week's 28-25 win against the Saints. Part of the issue appears to be edge rusher Danielle Hunter's ongoing adjustment to his role as a 3-4 edge. Hunter jumped an inside gap a couple times when Saints runners bounced outside for extra yardage, including a 6-yard run by Latavius Murray in the video below.

"[He's] getting used to this role," Donatell said. "Very normal, but we're very glad to have him, OK? Let's make that clear."

The Vikings rank 17th in yards per carry allowed and 26th in rushing first-down rate allowed, surrendering three rushing first downs and two rushing touchdowns when the Saints marched to take the lead in two drives.

The Bears' running back duo of David Montgomery and Khalil Herbert is on par with the Vikings' Dalvin Cook and Alexander Mattison for missed tackles forced this season, according to Pro Football Focus, making them the engine driving Chicago's offense.

New Bears offensive coordinator Luke Getsy, the ex-Packers quarterbacks coach, is overseeing an offense that leans on play-action passing when Fields does throw and a diverse run game featuring zone-read options and jet sweeps involving receivers.

"They make guys miss," defensive tackle Dalvin Tomlinson said. "They're good at breaking tackles. So you gotta bring your body when you tackle and get them on the ground as soon as possible."

The Vikings need better from Hunter, who leads the team with five missed tackles, via PFF, but also from an interior defensive line behind starters Phillips and Tomlinson. The Saints gained 5.9 yards per carry on 10 attempts when Phillips was off the field last week, compared to 3.4 yards when he was in the game. The Vikings promptly signed 338-pound nose tackle Khyiris Tonga for depth this week. Meanwhile, the Bears lost a solid offensive lineman, left guard Cody Whitehair, to injured reserve.

Vikings defenders don't get extra help in Donatell's scheme, which often has the secondary playing farther off the line in shell-type coverages. The Vikings also often play in "nickel" personnel, which removes a defensive lineman for an extra defensive back. Sunday might be the time for more base personnel and to play closer to the line. Otherwise the Bears can hit plays like this 12-yard run from Herbert against the Giants last week.

Fields has as many rushing attempts (34) as completions so far, and half of his carries have been scrambles while dropping back to pass. That's also front of mind at Vikings headquarters, where defenders at every level say they have to be wary of Fields escaping the pocket in a moment's notice.

The Vikings got a taste against Eagles quarterback Jalen Hurts, and it was one of the only areas defensively where they played well in that game. Hurts was limited to four scrambles in the Vikings' 24-7 loss and didn't gain a first down. Much of his damage was done on designed runs, like the 26-yard touchdown off the right edge.

Fields will both keep an option and run to the sideline and improvise on a passing play.

"He's that dual threat," Donatell said. "He has that working for him. He's been very effective with his legs, and he can extend the plays. You've gotta defend the first play, and you've got to defend the second play that's coming."