The Bears' NFL-worst run defense against Adrian Peterson appears to be a gross mismatch.
The Vikings are No. 5 in average gain per run and 11th in rushing yards. Peterson is second in the NFL with 997 yards on the ground and has an NFL-best 10 rushing touchdowns.
"We take a lot of pride in being able to run the ball," Vikings coach Les Frazier said. "That's our strength on offense, and we go into every ballgame with the intent of being able to run the ball. We feel like we've got the best running back in the NFL on our team, so we're going to try to play to our strength. That's our goal every week."
The Vikings ran for 123 yards in their 31-30 loss in Week 2 to the Bears at Soldier Field, but they needed 33 attempts to do so. Peterson had an even 100 yards on 26 carries.
But the Bears have been trampled underfoot in recent weeks by runners much less accomplished than Peterson. In the past five games they've allowed an average of 197 rushing yards per game. The NFL average is 111.
The coaching staff believes better alignment in run fits and assignment discipline will help. The question is: How much will it help?
"There's evidence there that we can get the job done, and that's the way we're starting the week," coach Marc Trestman said. "That's what we as coaches are trying to do is to continue to work at that and put ourselves in a better position to make those stops. We know we can't make all of them, but No. 1 is to minimize the explosive plays, and No. 2 is to begin to create some turnovers, which we haven't done the last couple weeks."
The Bears have not recovered any of the last 9 fumbles they forced, covering seven-plus games. After intercepting 9 passes in the first six games, the Bears have picked off just 5 in the last five.
The Vikings' passing attack is mediocre, but the threat of Peterson running roughshod over a defense that will sell out to stop him should help set up some play-action opportunities for quarterback Christian Ponder.
Safeties Major Wright and Chris Conte will frequently crowd the line of scrimmage to give the Bears eight in the box in an attempt to contain Peterson. But that often comes at the expense of pass coverage.
"Whenever you struggle with the run game and you have to put a lot of people at the line of scrimmage to defend the run, it'll make you susceptible to some plays down the field," Frazier said. "Now it's a matter of: Do you have the guys in the secondary that can make those plays?"
The Bears are No. 2 in interception percentage, one of the rare defensive categories in which they don't rank near the bottom of the league. But both safeties have struggled with missed tackles most of the season.
"You have to do what you have to do to stop the run if you're having trouble," Frazier said. "The (Bears) are putting more people at the line of scrimmage to help them in that way. It can make you vulnerable. It just depends on your guys in the secondary."
That's not a pleasant thought for the Bears, and even coach Marc Trestman would agree that a failure to slow down the runs game creates problems all over the field.
"When you're not stopping the run, you put your team in a (difficult) position," Trestman said. "Because now you've got not only play-action passes, but you've got the threat of explosive plays, because you're creating 1-on-1s on the outside.
"The sooner a team can make (an opponent) one-dimensional, they eliminate play-action passes and give themselves more options. They know they're going to be in drop-back modes, and the play-actions won't be as big a factor."
If the Bears can take Peterson out of the game and force the Vikings into obvious passing situations, they could make it 3 wins in their last four games in Minnesota. But in 11 career games against the Bears, Peterson has rushed for 1,185 yards and 14 touchdowns on 243 carries, a 4.9-yard average.
•Follow Bob's NFL and Bears reports on Twitter @BobLeGere.