LAKE FOREST, Ill. (AP) The Chicago Bears' defense is finding it difficult to close out games and showing signs of some real wear and tear.
Playing without injured linebacker Brian Urlacher and with several other lineup changes, the Bears will have to find a way to turn it around Sunday against a Minnesota Vikings offense that can run opponents into the ground behind Adrian Peterson. A win would also help erase the sting of the 23-17 overtime loss to Seattle at Soldier Field last weekend.
``That locker room, I know a lot of guys left that field pretty (ticked) off and you want another opportunity like that because games like that you shouldn't allow to slip away,'' linebacker Lance Briggs said. ``And we've done that more than once this year. We need to show up in the critical situations.''
The Bears defense has failed on three of the last four attempts when handed an opportunity to close out a game. Tim Tebow also beat them last year in overtime after rallying the Broncos on their final drive of regulation.
With five 30-something players, the conditioning and stamina of the defense has been closely watched. They allowed Seattle to convert eight of 15 third downs, a season's worst 53 percent.
``Third downs are critical in this league, critical,'' Bears defensive coordinator Rod Marinelli said. ``You've got to get off the field, because our offense does a nice job of controlling the clock. That's something we've been pretty good at through most of the year but that's something we have got to be on top of.''
The Bears have also allowed seven scores in the closing 3 1/2 minutes of the first half.
Staying fresh against Peterson, the NFL's rushing leader, and a Vikings offense that is likely to stress ball control with top wide receiver Percy Harvin now on injured reserve (ankle), isn't likely to be easy. Doing it without Urlacher, and with different players manning four positions on defense will be even more difficult.
Without Urlacher for at least three weeks due to a pulled hamstring, the Bears are moving Nick Roach to the middle linebacker and replacing him on the strongside with free agent acquisition Geno Hayes.
The Bears did not consider moving Briggs from his weakside linebacker spot to the middle because they didn't want to weaken his position while also playing with an inexperienced middle linebacker.
``This is my 10th year and I've never played Mike (middle backer) in my 10 years,'' Briggs said. ``It would be easier for me to play Sam (strong), it would be easier for me to play nickel (back) than it would for me to play Mike. I could play it. All of us could play it because the positions are interchangeable. But I don't want to play it.''
Coach Lovie Smith supports Briggs' stance.
``Will we ever do that? No,'' he said. ``Lance won't be playing `Mike' linebacker unless we have everyone else go down and then we would maybe call on him then, but that's not a part of what we're looking at.''
Hayes was a weakside linebacker in Tampa who has been playing strongside in Chicago. The other changes will likely be Kelvin Hayden moving from nickel back to starting left cornerback for injured NFL interception leader Tim Jennings, who missed a second straight practice with a shoulder injury, and D.J. Moore replacing Hayden at nickel back.
The changes could make it tough for a defense that has been struggling against the run. No one rushed for more than 106 yards against the Bears in the first six games. No one has rushed for less than 114 against them in the last six and Peterson is coming off a 210-yard performance against Green Bay, his sixth straight 100-yard game.
``I'm pretty sure that the main thing that makes their offense tick is Adrian Peterson, so our main goal is to stop him and to force them to try to go to their second option,'' Hayden said.
NOTES: Wide receiver Earl Bennett has been ruled out for Sunday's game due to a concussion. ... Wide receiver Alshon Jeffery (knee) and wide receiver Devin Hester (concussion) practiced on a limited basis for the second straight day. ... Running back Michael Bush missed a second straight practice due to a rib injury, but Smith said he expects Bush will be ready to play Sunday.