In their previous four games, the Vikings defense allowed just 12 third down conversions out of 50 opportunities.

The Bears nearly matched that many third down conversions in one game. They went 10 of 17 on that specific down in the Vikings' 21-13 loss at Soldier Field on Sunday.

"We didn't cover, it's that simple," Vikings head coach Mike Zimmer said.

The Vikings blew their coverage assignments at times on third downs with quarterback Jay Cutler proving once again how dangerous he can be improvising on the run. Missed tackles also contributed to the third down struggles. Rookie linebacker Anthony Barr, who has become about as sure of a tackler on the team this season, missed three tackles on the Bears first offensive drive.

Vikings defensive players said Cutler got rid of the ball quickly on third downs to avoid pressure, relying on wide receivers Alshon Jeffery and Brandon Marshall to make contested catches. They did all game, combining for 225 on 18 catches and three touchdowns.

"In situations like that when the ball is coming out quick and your rush can't get there you have to get your hands up, help your [defensive backs] as much as you can and your [defensive back] has to make the play," linebacker Chad Greenway said.

Due to the previous four game stretch, the Vikings entered the game with the 10th best third down percentage (37.6) despite their early-season issues on that specific down.

Even with the bye week, and what the Vikings called a good week of practice, the defense regressed in that area and kept the Bears offense on the field for over 38 minutes.