LAKE FOREST, Ill. – After failing to record a sack last weekend in Atlanta for the second time in four games, the Bears need their pass rush to return with a vengeance Sunday when they host the Minnesota Vikings.

Marcus Harrison pressures Falcons quarterback Matt Ryan in last Sunday's 22-20 loss to Atlanta.

“I’m surprised whenever we don’t sack the quarterback,” said coach Lovie Smith. “Everything starts off with being able to get pressure with our front four.

“If we’re not getting a lot of sacks, you should at least see interceptions on the other end. The quarterback’s getting rid of the ball quickly, which should allow us an opportunity to get some picks. If both of those don’t happen, it’s not a good day for us.”

Such was the case last Sunday against Falcons rookie quarterback Matt Ryan, who completed 22 of 30 passes for 301 yards and 1 touchdown with no sacks or interceptions in a 22-20 win over the Bears. Ryan not had thrown for more than 194 yards in his previous five NFL games.

“It’s very frustrating,” said defensive end Adewale Ogunleye, who has just 1½ sacks in six games this season after leading the Bears with nine sacks last year. “I’ve got to make the most of my opportunities.

“It starts with me up front, but there were times [in Atlanta] when I was unblocked and I still wasn’t getting to him on time because he was getting the ball out that fast. With that being said, we’ve all got to play defense together. The DBs and the defensive line have got to play off each  other. We need them and they need us.”

The Bears failed to record a sack on 97 pass attempts in their last two losses to the Buccaneers and Falcons. In between, they compiled seven sacks in back-to-back victories over the Eagles and Lions.

On Sunday, the Bears will face a Vikings offense that ranks 21st in the NFL in sacks per pass attempt this season. Last weekend, Minnesota quarterback Gus Frerotte was sacked five times in a 12-10 win over the Lions.

“Anything we do in the pass game starts with the pressure and that makes everything go,” said defensive coordinator Bob Babich. “We need to get it done. We need to get more sacks, and hopefully it’ll work out this week.”

Just for starters: The Bears have not scored an offensive touchdown in the first quarter in four of their last five games, including the past two contests against the Lions and Falcons.

“It’s one thing that we’ve been talking about,” said offensive coordinator Ron Turner. “An area that we can improve is starting fast, coming out and executing and making some plays.”

“It’s very crucial,” said tight end Desmond Clark, “especially playing at home because you want to get the crowd into it and get them involved early so it creates difficulty for the opposing team.

“Whenever you can get off to a big early start, the other team has to dig out of a hole and possibly get off their game plan a little bit and do some other things that they might not have wanted to do.”

Orange swarm: The Bears are encouraging their fans to join them in wearing orange to Sunday’s game against the Vikings. Chicago is 2-1 when wearing orange jerseys at Soldier Field, having defeated the 49ers 17-9 in 2005 and 41-10 in 2006 before losing to the Lions 16-7 last season.

“We’re asking all of our fans to wear orange,” Smith said. “We need a sea of orange. We need all of their support, and hopefully we’ll give them something to cheer about from start until the finish.”

Health beat: Cornerback Charles Tillman (shoulder), nickel back Danieal Manning (hamstring), receiver Brandon Lloyd (knee) and punter Brad Maynard (hamstring) did not practice Wednesday.

Players who were limited included receivers Marty Booker (back), Rashied Davis (knee) and Devin Hester (toe); defensive tackles Tommie Harris (knee), Marcus Harrison (ankle) and Israel Idonije (ankle); cornerbacks Nate Vasher (wrist) and Trumaine McBride (shoulder); and linebacker Nick Roach (shoulder).

Cornerback Marcus Hamilton (heel) practiced without restrictions.

For the Vikings, linebacker David Herron (hip) did not practice; and receivers Bernard Berrian (knee) and Sidney Rice (knee), linebacker Erin Henderson (knee), tight end Jim Kleinsasser (foot), cornerback Benny Sapp (hamstring) and safety Madieu Williams (neck) were limited.