CHAMPAIGN -- New Illinois coach Tim Beckman knows from experience that Western Michigan likes to put the ball in the air.
Beckman said Tuesday that the key to defending the Broncos in Saturday's season opener will be to keep fresh legs on the field -- he just doesn't know if he has the depth on defense to do it. At least he has four games to find out before the conference opener Sept. 29 against Penn State.
"That's one of the things that prior to going into the Big Ten is a question that has to be answered -- how good are our backups?" Beckman said. "The game of football's a tough game. It lasts a long time."
Illinois will be without defensive end Justin Staples, suspended for the opener after he was arrested earlier this year on a drunken-driving charge. Junior Tim Kynard will start in his place. Injuries could also keep safeties Supo Sanni and Steve Hull out.
Beckman replaced Ron Zook last winter, moving from Toledo where his teams regularly faced the Broncos as a Mid-American Conference opponent.
While the Illini survived 48 passes by Bronco quarterback Alex Carder last season in a narrow 23-20 win, Beckman knows what Western Michigan looks like when it really opens up the offense.
Carder threw the ball 59 times in Toledo's white-knuckle 66-63 win over the Broncos last season. He completed 38 of those passes for 548 yards and seven touchdowns. Carder's counterpart on Saturday, Illinois' Nathan Scheelhaase, threw just 13 touchdowns all of last season.
"They move at such a fast pace, and Western Michigan has always done that," Beckman said. "We've got to keep fresh bodies on the field so we can rush the passer and we can also get the routes covered."
Beckman said he has challenged some younger defenders to contribute from day one.
One of those younger players who could have helped is lost for the season. Sophomore linebacker Henry Dickinson was pushing Houston Bates for starting time at one linebacker spot before he broke his right leg in practice two weeks ago.
Two keys to pressuring Carder will be defensive end Michael Buchanan -- who was No. 2 on the team and fourth in the Big Ten last fall with 7 1/2 sacks -- and defensive tackle Akeem Spence.
Both could have been gone to the NFL this season -- along with cornerback Terry Hawthorne -- and in past years likely would have been gone, Beckman said. The Illinois defense will likely be built around those three, along with linebacker Jonathan Brown.
"They had opportunities if they would have liked to go out early. That had been the norm here at Illinois," Beckman said. "They're outstanding football players. They're buying into what we're doing here."
Hawthorne is one of the team's fastest players and is expected to see time at both wide receiver -- another position where Illinois is short on depth -- and returning punts and possibly kicks. Beckman said the senior will be limited to defensive work this week and for at least another week or two beyond.
"He had a little ankle sprain early during two-a-days here," which limited his ability to work on offense, Beckman said.
Hawthorne was one of Illinois' top high school receivers when he came to the Illini from East St. Louis after the 2008 season.