DES MOINES, Iowa – It's hard not to be drawn in by the dazzling array of quarterbacks in the Big Ten this season.
From fleet-footed stars like Michigan's Denard Robinson and Nebraska's Taylor Martinez to traditional standouts like Russell Wilson of Wisconsin and Michigan State's Kirk Cousins, the conference has more than enough signal callers to get excited about.
That doesn't change the fact that the league title will likely be decided on the other side of the ball.
"If you're going to be a champion in this conference, you've got to play great defense," Michigan State coach Mark Dantonio said. "If you look at every football team that's won the conference in the past 10 years, and for that matter for us last year as co-champions, these teams are ranked somewhere in the top four in the conference."
It's hard to see that changing in 2011.
Seven of the nation's top 20 stingiest defenses in the Big Ten, which begins conference play this weekend.
Wisconsin leads the way, third overall with just 8.5 allowed points per game, followed by Michigan State (eighth at 11 ppg) and Penn State (10th with 12.5). Illinois, the resurgent Wolverines, Ohio State and Purdue all allow 16 points or less per game so far.
For all the talk about Wilson and the offense's brilliant start, the Badgers defense hasn't taken a back seat to anyone. The seventh-ranked Badgers (4-0) host No. 8 Nebraska (4-0) in the Cornhuskers' league debut on Saturday.
Martinez and Rex Burkhead have keyed one of the nation's top rushing offenses. But Martinez is completing just 50.6 percent of his passes, and he'll be facing a much better defense than he saw last week in Wyoming, whom the Huskers rolled past 38-14.
Wisconsin has allowed just 17 points in the last three weeks.
"They're very sound. They just do what they do and they do it well," Nebraska coach Bo Pelini said. "They play with good technique. They tackle well, which I think all good defenses have that characteristic. And they execute what they're trying to do and their schemes are well thought out."
Michigan State (3-1), which plays at Ohio State (3-1) this weekend, leads the nation in total defense with just over 172 yards allowed per game. But Notre Dame hung 31 on the Spartans on Sept. 17 and the Spartans will now face Braxton Miller, the dynamic young Buckeyes quarterback.
Miller only threw for 83 yards on five completions last week, but two went for touchdowns in a 37-17 blowout of Colorado.
"We didn't throw the ball great, and I think early on the ball wasn't coming out of (Miller's) hand great," Ohio State coach Luke Fickell said. "Was that nerves, was that some other things? I don't know. Settled down, threw some good balls, so we believe we can get it rolling."
Penn State (3-1), which plays at Indiana (1-3) on Saturday, could have trouble keeping up its strong early pace on defense because of injuries.
Starting linebacker Michael Mauti will miss the rest of the season after tearing the ACL in his left knee in last week's 34-6 win over Eastern Michigan. Cornerback D'Anton Lynn was carted off the field on a backboard and taken to a local hospital, and his status for this week's game was unclear.
No. 24 Illinois (4-0), who survived a scare from Western Michigan after holding Arizona State to just 14 points, concludes a five-game homestand this week with Northwestern (2-1). The Wildcats could see the return of quarterback Dan Persa after a lengthy recovery from a ruptured Achilles tendon.
"It's a big boost. He's who's battle tested, been through a lot," Northwestern coach Pat Fitzgerald said. "He's worked so hard to get himself back, and it's been a long road."
No. 19 Michigan also allowed 31 points to the Irish but managed to pull off one of the most thrilling victories of the young season. The Wolverines have allowed just 10 points since in wins over Eastern Michigan and San Diego State.
First-year coach Brady Hoke isn't exactly thrilled with his defense, which has bailed itself out of trouble by forcing 13 turnovers.
"We don't play with any consistency. When you look at runs and big plays and those kind of things, I think we give up way too many of those," Hoke said. "We've got a lot of physicalness that we need to bring to the table as a defense, and I think what's helped us to some degree is the ability to get some turnovers at critical times."
Purdue (2-1) will get a chance to show that its 59-0 win on Sept. 17 over Southeast Missouri State, its first shutout in seven years, wasn't a fluke when they host Notre Dame (2-2) Saturday night. The Boilermakers have produced mixed results so far, with a 27-24 home win over Middle Tennessee State and a 24-22 loss at Rice.
The only Big Ten team with the week off is Iowa (3-1), a surprise no-show among the list of the league's top defenses. But the Hawkeyes made significant changes after letting up 44 points in a triple-overtime loss at Iowa State and have allowed just 20 points in the last five quarters.
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