LAKE FOREST, Ill. -- Chicago Bears coach Marc Trestman wouldn’t blame CBA rules limiting contact in practices for the team’s poor tackling performance in Week 1, but knows that’s an area of the game that needs to improve for Sunday’s matchup against Minnesota running back Adrian Peterson.

“I couldn’t comment,” Trestman said when asked about the CBA affecting his team’s tackling. “I can’t really stand up here after coaching a week in this position in the National Football League and start making statements that I really am not educated enough to do at this time. You kind of hear that across the league right now. We’re just focusing on doing what we need to do this week and that’s tackle better.”

If the Bears fail to do so on Sunday, they know Peterson can take over the game.

The last time the teams met, Peterson shredded the Bears for 104 yards in the first quarter and a pair of touchdowns. In the first matchup between the clubs last season, the Bears limited Peterson to 108 yards, but did that by putting the Vikings in passing mode early. Chicago scored three touchdowns in the first half on the way to building a 28-10 lead at intermission.

One of the key points of emphasis for the Bears this week will be getting off the field on third downs, but not solely for the sake of preventing first downs and stalling drives. Along the offensive line, the Vikings like to experiment with hitting different points at the line of the scrimmage over the course of a game until they find an area of weakness.

By getting off the field on third downs, the Bears limit their exposure to Minnesota’s coaching staff as they search for that area of vulnerability.

“It’s a difficult, huge challenge (stopping Peterson). He’s one of the better ... no he’s one of the best backs to ever play the game, so everyone’s got to do their job,” defensive coordinator Mel Tucker said. “Everyone has to be at the point of attack every time he gets the ball. Frontside, backside, D-line, linebackers, secondary, every time he gets the ball he can go the distance and we know that. Tackling is going to be huge for our whole defense. That’s one of the things we’ve been talking about: we have to become stronger tacklers, and that’s a point of emphasis.”

But tackling Peterson isn’t the same as putting licks on most ball carriers, according to cornerback Charles Tillman, who said the running back is incomparable to every player at his position.

“He’s in a league of his own,” Tillman said. “He was definitely the MVP for a reason last year. Our defense will have our hands full. You can’t just have one guy tackling him. You want to have a population tackle.”

Can the Bears consistently pull that off? They think so, but haven’t lost sight of the fact that five of Peterson’s 37 career regular-season games in which he gained 100 yards or more came courtesy of the Bears. In fact, the Bears have surrendered three of Peterson’s longest career runs (73 yards, 67 and 59).

That’s part of the reason why last week’s poor performance plays prominently in the defense’s collective psyche. But the Bears are confident they’ll improve their tackling.

“It’s only Week 1. There’s no point to getting frustrated right now,” defensive end Shea McClellin said. “We have 15 more opportunities to get better and improve.”

As for the notion that the CBA has adversely affected Chicago’s tackling, even if the rules didn’t exist, the Bears would still limit contact at practices.

“Lance [Briggs] said [the Bears tackled poorly] immediately after the game and [defensive coordinator] Mel [Tucker] said that,” Trestman said. “We all know that. It’s part of the preseason too, where we don’t tackle during the preseason or training camp. Even if we had a chance we wouldn’t because we want to get our guys to the season safe. So we know there’s a cost-benefit to not doing more of it. Thankfully, we were able to get through the first game and we’ll be better this week.”