It’s the Charge of Light Brigade

Ask the guys who play along the line or in the secondary. Ask anyone on the USC defense about Notre Dame and the answer is pretty much the same.

For them, it isn’t just the gold helmets and “Touchdown Jesus” that make this rivalry special. It’s the massive Irish offensive line. It’s the hitting.

“Every season is the same,” defensive end Lonnie Ford said. “Notre Dame is smash-mouth football.”

Last season, that translated into a bruising defeat. Now, Ford and his teammates head into a rematch with a revamped defensive philosophy that seeks to blunt the stampede by going smaller .

If that seems counterintuitive, think David and Goliath. Think quick linemen who shoot the gaps, linebackers and safeties who fly to the ball.

“Size says a lot,” safety Troy Polamalu said. “But we swarm.”

In theory, that is how it works. In reality, this season’s version of the USC defense has produced mixed results, ranking first in the Pacific 10 Conference against the pass and last against the run. The Trojans surrendered 203 yards rushing to Stanford, a whopping 340 to Kansas State.

But with their young linebackers sound for the first time in a month, they showed improvement against Arizona State’s veteran line last week. Coach Pete Carroll insists his players are growing more comfortable with their new scheme, missing fewer assignments, making more plays.

The transformation began when Carroll was hired last December. Having spent nearly two decades as a defensive specialist in the NFL, he looked around the Pacific 10 Conference, saw more than a few spread offenses, and decided to fight speed with speed.

Safeties became linebackers, a cornerback shifted to safety. Even big linemen went through an off-season conditioning program that emphasized shedding pounds.

More recently, the defense got even smaller when 315-pound nose tackle Bernard Riley suffered a season-ending injury and 255-pound Shaun Cody moved from defensive end to the interior, into the land of 300-pounders.

On Saturday, this lighter lineup faces a Notre Dame team with a history of grinding out yards since the days of the Four Horsemen.

The line that blocked for those storied backs was known as the “Seven Mules” and was anchored by a kid from Hollywood, center Adam Walsh, who weighed only 187 pounds. These days, the line is considerably larger but operates on the same premise, letting blockers such as 312-pound tackle Kurt Vollers and 249-pound fullback Tom Lopienski lead the way.

“A very physical team,” Carroll said. “They’d just as soon run it down your throat if they can.”

That’s what happened last November at the Coliseum. Toward the end of the game, with USC trailing by only a touchdown, Notre Dame ran 24 consecutive times. That translated into one drive for a field goal, another for a touchdown and enough time off the clock to seal a 38-21 victory.

Polamalu, who likes to think of himself as a physical player, remembers receiving far more blows than he delivered that day.

But five weeks later, in the Fiesta Bowl, Notre Dame was held to 17 yards on the ground and embarrassed, 41-9, by a smaller Oregon State team. Although the new USC defense differs considerably from what the Beavers employed, Carroll watched tapes of that game and learned a lot about disrupting the Irish offense.

“You try to beat them with pursuit and stunting,” he said. “You try to get penetration.”

It starts with a player such as Cody, who gives up 40 pounds against the Irish guards but thinks he can use his quicker hands to fight off blocks. Quicker feet, he hopes, will help him get off the line and into the backfield.

Outside linebackers Frank Strong and Matt Grootegoed--each of whom missed earlier games because of injury--will be called on for run blitzes and pursuit.

Notre Dame Coach Bob Davie expressed concern about USC’s ability to bring support from the secondary.

“They’re gonna drop those safeties into a nine-man front,” he said. “It’s hard to survive with running ... from a two-back backfield. The quarterback needs to make some plays.”

Sophomore quarterback Carlyle Holiday isn’t expected to throw more than 15 or so passes Saturday. Instead, he will try to strike with the option, which both Kansas State and Washington used successfully against USC. Holiday, who started for the first time three weeks ago, has averaged 126 yards rushing in the last two games.

He can also hand off to one of three backs--Tony Fisher, Julius Jones and Terrance Howard. Fisher and Jones skipped practice Monday because of what Davie called minor injuries, but they are expected to play. USC recalls all too clearly how that trio combined for 189 yards and three touchdowns at the Coliseum last season.

So Carroll and his defense must prove their approach can work against a bigger team. They must be quick enough to contain the option and offset Notre Dame’s brute force or face a repeat of last season, one rushing play after another.

“If it’s going to be like that,” Carroll said, “it’s going to be very difficult.”