Vikings face another tough RB-WR combination in Chicago

They are not matched sets.

Detroit receiver Calvin Johnson is faster, Chicago's Brandon Marshall perhaps a bit stronger. Lions running back Reggie Bush is quicker, Bears back Matt Forte shifty and strong.

But the effect of either one-two punch can be painful.

"There are similarities," Vikings linebacker Erin Henderson said. "But they are also their own animal. But both are effective.''

And so, this week, the Vikings are preparing for a Chicago Bears team that presents a problem similar to last week. Which poison to pick? Should the focus be on the big-play receiver or the running back?

What's most important, preventing the big play downfield or worrying about the running game and short passing game to the running back, particularly screen passes?

While prepping for the opener at Detroit, Vikings coordinator Alan Williams said if you tried to defend everything you're not going to defend anything.

Teams will continue to use Detroit's blueprint until the Vikings prove they can stop it. And that means more screen passes.

"Absolutely," linebacker Chad Greenway said. "We expect that. We know we have to do a better job recognizing the screens and then coming up and making the tackles. Until we show we can do that, teams aren't going to stop."

Williams felt last week's plan was strong, the execution not so. The Vikings were too porous up front against the run, which translated into too many short second-down plays for Detroit. The Vikings also lost Bush too often in the short passing game.

The key?

"We just have to tackle better," Williams said Thursday. And he was talking both about the problems in the run and the work against the short passing game.

Chicago figures to be more of a balanced attack than the Lions. The Bears appear more determined to run the ball. And Forte, who has averaged 69.8 rushing yards in nine career games vs. the Vikings, isn't as elusive as Bush.

Still, Marshall and Forte present a challenge. Marshall caught 22 passes for 252 yards and a TD in two games vs. the Vikings last season. This year he has continued to be Bears quarterback Jay Cutler's go-to receiver.

In Chicago's victory over Cincinnati Cutler targeted Marshall 10 times, completing eight for 104 yards and a score.

"They're similar body type-wise," cornerback Chris Cook said, comparing Marshall and Johnson. "Both guys are bigger guys as receivers, and they like to play physical.''

Forte, meanwhile, might not be as explosive as Bush. But he's a capable runner and a very good receiver.

So the key will be to limit big plays over the top, and then do a better job along the line. Williams said several players took bad angles on Bush's 77-yard score.

The anticipated return of Kevin Williams should help shore up the run defense. And, given the Bears attack, the Vikings figure to be in their base defense — with a third linebacker — more often than in Detroit, where the Vikings played mainly in their nickel set.

But it will important for the entire front seven to make sure Forte is corralled quickly after catching the ball — something the Vikings didn't do with Bush.

"It was, for the lack of a better word, embarrassing watching it on tape," Robison said. "We had so many missed tackles in that game. We have to shore that up this week, make sure we get two hands on 'em, bring 'em to the ground.''