Another major test for Trojans : Team’s secondary must deal with Stanford’s impressive duo of Luck and Gerhart.

USC’s secondary is a veteran group, featuring starters with four, five and even six seasons of college experience.

Cornerback Josh Pinkard played in the 2005 Bowl Championship Series title game against Oklahoma.

Pinkard and cornerback Kevin Thomas also played in the 2006 BCS title game against Texas.

And safety Taylor Mays has started all but two games in four seasons.

The Trojans will need all of their collective savvy, along with safety Will Harris’ playmaking ability, when 11th-ranked USC plays No. 25 Stanford at the Coliseum today.

Stanford’s Andrew Luck is an accurate passer and productive runner, a redshirt freshman whom Cardinal Coach Jim Harbaugh has called “the best quarterback in the country.”

That would be a challenge for any secondary.

But Stanford also features Toby Gerhart, a former Norco High star who is the nation’s second-leading rusher.

In USC’s last go-round against an opponent with a multiple-threat offense, the Trojans surrendered 613 yards two weeks ago at Oregon in their most lopsided loss in Coach Pete Carroll’s nine seasons.

Quarterback Jeremiah Masoli and pint-sized running back LaMichael James ran through the Trojans’ front seven, forcing the secondary to make the majority of tackles.

The Ducks’ spread attack is at the opposite end of the spectrum from Stanford’s smash-mouth style, but USC’s secondary prepared this week for the possibility of another day of double duty.

“If they’re breaking plays, this is a big challenge,” Carroll said. “The secondary will need to finish a lot of tackles.”

At 6 feet 1 and 235 pounds, Gerhart is tough to bring down.

He averages 135 yards rushing a game and has twice run for 200 or more.

In last week’s 51-42 win over Oregon, Gerhart ran for 223 yards and three touchdowns in 38 carries.

“He really lifts our football team at times onto his back and carries them,” Harbaugh said.

Gerhart might have carried the ball for the Trojans had he not been recruited by USC mainly as a fullback or linebacker. He also wanted to play baseball and chose the Cardinal, in part, because he would be allowed to pursue both sports.

“I couldn’t tell that he would be such a dynamic football player and really control the whole environment of a team,” Carroll said. “They’ve just built their image around him.”

Their offense too.

Gerhart, averaging 26 carries a game, has scored 16 touchdowns.

“This is straight up, ‘We’re giving him the ball and running right at you,’ ” Mays said.

Luck also can run, which could be bad news for a Trojans defense that allowed Masoli to romp for 164 yards.

The 6-4, 235-pound Luck is the Cardinal’s second-leading rusher, and his average of 5.2 yards a carry matches Gerhart’s.

“That could be an issue for us,” Carroll said of Luck’s running ability. “We’re going to try and keep him corralled and not let him get out.”

Allowing Luck to remain in the pocket could be even more problematic.

The Pacific 10 Conference’s leader in passing efficiency, Luck has completed 58% of his passes for 11 touchdowns with three interceptions.

Against Oregon, he passed for 225 yards and two touchdowns.

So the Trojans’ secondary is on the spot.

The unit was shuffled during training camp when cornerback Shareece Wright, a 2008 redshirt because of a neck injury, was declared academically ineligible.

Pinkard, who had returned for a sixth season so he could play safety -- his projected position in the NFL -- moved to cornerback for the second year in a row.

In September, Mays suffered a knee injury against Ohio State that forced him to sit out against Washington, a game the Trojans lost when Huskies quarterback Jake Locker completed several passes during a game-winning drive.

The secondary also had problems against Notre Dame, Oregon State and Oregon, but rebounded from the loss at Eugene to shut down Arizona State in a 14-9 victory last week.

Harris, a fifth-year senior, intercepted two passes against the Sun Devils, returning one for a touchdown.

Now, according to Harris, the secondary is ready for Stanford.

“We love when the burden is on us,” he said.

gary.klein@latimes.com

twitter.com/latimesklein

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No. 11 USC vs.

No. 25 Stanford

Today at the Coliseum

12:30 p.m., Prime Ticket

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(BEGIN TEXT OF INFOBOX)

Running roughshod

TOBY GERHART’S RUSHING CAREER AT STANFORD:

*--* Year G-GS Att. Yds Avg. Long TD 2006 12-1 106 403 3.5 38 0 2007 1-0 12 141 11.7 48 1 2008 12-12 210 1,176 5.4 46 15 2009 9-9 233 1,249 5.2 60 16 Totals 34-22 561 2,969 5.3 60 32 *--*