OXFORD, Miss. -- Ole Miss knows about its opponent in Thursday's opener in Atlanta. But the 18th-ranked Rebels are going to have to wait until the ball's kicked off before they know exactly what they're going to get from their opponent.

The Rebels are more than a week into preparations for Boise State, the new-look Broncos are making formulating a game plan more difficult than usual.

Boise State has a new coach in former offensive coordinator Bryan Harsin, who left Arkansas State after one season to replace Chris Petersen. Harsin, who coordinated the Broncos' offenses from 2006-2010, has the brought with him a new staff, including offensive coordinator Mike Sanford, who's calling plays for the first time after spending the last three seasons as an assistant at Stanford.

"It's definitely difficult on the (defensive) staff because the coordinator that's been hired has not been a coordinator before," Ole Miss coach Hugh Freeze said. "I'm sure he'll take something from everywhere he's been just like all of us did, but you're just not quite sure what his flavor is. That's a bit difficult."

Arkansas State's spread offense averaged 29.2 points in Harsin's only season at the helm, and his background as a playcaller at Texas and Boise State gives the Rebels an inkling of what to expect. But Ole Miss will look back at all of previous stops for Harsin and Sanford to get a more complete idea of what it could see from the Broncos at the Georgia Dome on Thursday.

That also goes for the Broncos' defense, which is breaking in a new coordinator in former Texas A&M co-defensive coordinator Marcel Yates.

All that film study won't cover everything, which has the Rebels prepared to execute what they do regardless of any new wrinkles they may see.

"It's difficult just because we've had to look at two teams and three different years of film just to kind of get a feel for what they're going to do," Wallace said. "But at the same time, (our) tempo, it can help us if they come out in something totally different. We can just go to tempo. That's what I'm comfortable in."

But Ole Miss is exhausting all avenues to get familiar with the Broncos.

"It's not the easiest thing in the world," Freeze said, "but it happens."