Oregon isn’t all about offense

Reporting from Eugene, Ore. — Just to be clear, Michael Clay does not want to sound like a complainer.

The linebacker understood when he signed with Oregon he was joining a program known for its rapid-fire offense. For outracing opponents, not stopping them cold.

Defense is something of an afterthought.

“Can’t deny that,” Clay said. “We kind of fly under the radar.”

But this fall, with the fourth-ranked Ducks sneaking back into the national championship hunt, scoring almost seven touchdowns a game, Clay and his defensive teammates are starting to get noticed.

They frustrated Heisman Trophy favorite Andrew Luck in a lopsided win over Stanford last week. Now comes another test against Matt Barkley, who leads No. 18 USC into Autzen Stadium for a Pac-12 Conference showdown Saturday.

“Their defense is really good,” USC Coach Lane Kiffin said. “Probably the best it’s ever been there.”

At first glance, the statistics make that sound like normal pregame talk from a coach. Giving up an average of 384 yards a game, the Ducks rank around the middle of the conference.

But look closer.

Their offense, which can score as quickly as some teams go three-and-out, has left the defense on the field a wearying 797 plays. That’s 122 more than USC — almost two games’ worth.

“I’m not going to sit here and [lie to] you,” defensive coordinator Nick Aliotti said. “Sometimes it can be difficult.”

Where Aliotti’s squad shows its worth is in per-snap statistics, giving up only 4.8 yards, which would put the Ducks among the top 20 or so defenses in the nation.

“They cause you a lot of problems,” Kiffin said. “They’re all over the place.”

Much like the offense, the defense tries to confuse opponents with an array of looks from a variable scheme that can switch from 4-3 to 3-4 in an instant. But deception goes only so far.

The Ducks have to reach deep into their roster to keep fresh legs on the field for so many minutes. It’s not unusual for them to rotate seven or eight linemen, a handful of linebackers and seven or eight defensive backs.

“You’re not going to find anybody in the nation that rotates that many people and gets the results we do,” defensive end Terrell Turner said.

It also helps that they work against that offense for parts of each day’s practice, hustling through Coach Chip Kelly’s distinctively frenetic drills. In one regular segment, the ball is placed for a new snap even as the previous play is coming to an end.

“That’s full-tilt, hyper-speed,” Aliotti said. “You’d have to see it to really understand.”

The deep rotation necessitates playing some underclassmen and suffering through growing pains. Oregon has also missed All-American cornerback Cliff Harris, suspended multiple times for traffic tickets.

Harris sat out a 40-27 season-opening loss to Louisiana State, a game in which three turnovers left the Ducks continually scrambling to defend a short field.

Since then, they have matured enough to hold the likes of California and Washington to 17 points or fewer and would have shut out Colorado if not for a safety on Harris’ fumbled punt return.

A big part of the Ducks’ success comes from pressuring the quarterback, collecting a conference-best 32 sacks. Luck credited the front seven for pestering him into a subpar game that included a fumble and two interceptions, one of which was returned for a touchdown.

“They did a good job with stunts and blitzes,” he said.

Still, most of the talk this week has centered on USC needing to keep pace with Darron Thomas, LaMichael James and the rest of an Oregon offense that averages almost two touchdowns more than the Trojans.

Hardly anyone has talked about the Ducks who play on the other side of the ball.

Which is fine with them. If anything, the defense can see an advantage to being overlooked.

“We like being the underdog,” Clay said. “We can surprise people.”

david.wharton@latimes.com

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