He Plays Offense With Defensive Fire : USC: Pat Harlow became a standout as soon as he made the switch to the offensive line.

At the end of his sophomore season two years ago, Pat Harlow was USC’s fourth-best defensive lineman. Since the Trojans favor a 3-4 defensive alignment, that meant only one thing:

He was the odd man out.

What to do?

Tired of sitting, Harlow thought about transferring.

He thought about red-shirting.

Finally, he asked for a meeting with Coach Larry Smith, who suggested another option: Start over and move to offensive tackle.

Harlow agreed without hesitation and a star was born.

In only his second season at his new position, the 6-foot-7, 270-pound Harlow was named to the all-Pacific 10 Conference first team last month. And in a vote of the conference’s defensive linemen, he was named winner of the Morris Trophy as the Pac-10’s outstanding offensive lineman.

NFL draft analysts have said that Harlow could be among the top 10 picks in next spring’s selection process. He and Antone Davis of Tennessee are generally considered to be college football’s best offensive tackles.

What pro scouts and USC’s coaches seem to like most about Harlow is his aggressiveness, a trait that can be traced to his time spent on defense and a characteristic said to be in short supply among offensive linemen.

“I’ve noticed his real desire to make the block downfield--to finish what he’s doing, then make another block,” said Jerry Frei, a scout for the Denver Broncos. “You look for an offensive player with that defensive attitude, that kind of half-mean (demeanor).”

Harlow, who will play his final game for the Trojans Monday against Michigan State in the John Hancock Bowl, said he hasn’t made any adjustments in his attitude.

“I don’t really think there’s a defensive mentality or an offensive mentality,” he said. “It’s a football mentality. Everybody says offensive linemen have to be passive. I think that’s (baloney). Offense is to attack. Everybody thinks defensive players are crazy, and they are, but you have to be the same way on offense.”

Harlow was a two-way player at Norco High, where he was the Ivy League’s defensive player of the year, an All-Riverside County pick on both offense and defense and highly regarded as a senior.

But until the spring of his junior year at Norco, Harlow was partial to basketball, which he called “my love.” His girlfriend, Jennifer Mersereau, another Norco alum, has described him as a gym rat.

Contacted or actively recruited by several schools to play basketball, including Oregon, Arizona State and San Diego, Harlow almost quit football before a friend convinced him that his future was brighter outside the gym.

“I couldn’t jump really well,” Harlow said. “I could dunk and all that, but I didn’t have any serious hang time. I’m a pretty good athlete, but I couldn’t see myself hanging out with Michael Jordan.”

He took to weightlifting and in the four months before his senior year, Harlow increased his weight from 195 to 240 pounds.

Recruited as a defensive lineman, he made trips to Washington and Colorado before deciding on USC, in part because his high school coach, Gary Campbell, told him that he probably would end up being an offensive lineman.

“I was going to try defense, but the worst that could happen was that I would become a USC offensive lineman,” Harlow said.

USC has a tradition of producing top-notch blockers. Twenty of the Trojans’ offensive linemen have been first-team All-Americans since 1964 and 16 have been first-round NFL draft picks since 1968.

“Even when I was a kid, watching football on TV, I knew about USC’s offensive line,” Harlow said.

He started only one game as a defensive lineman, and grew frustrated and depressed as a backup to All-American tackle Tim Ryan, who was only a year older.

The coaches, too, saw that something needed to be done.

“We couldn’t see wasting another year of that kind of talent on the second-team defense,” Smith said.

So, Harlow was moved.

Smith told him that he would be dominant by the time he was a senior, but after helping the Trojans win the Pac-10 championship last season, Harlow missed the Rose Bowl game because of a herniated disk in his back.

After missing spring practice while recuperating from surgery, he returned a more passive player this season, although he didn’t fully realize it until he met with Smith after a 31-0 loss at Washington in September.

“I played terribly and the coaches just ripped me, which I deserved,” said Harlow, who wasn’t the only Trojan who faltered that day. “I don’t think I could have played any worse. Coach Smith told me, ‘You’re not even a shell of the player you were last year. You’re not pulling the trigger.’ ”

Given a poor grade by his coaches, a chastened Harlow posted it on his bedpost and wrote over it, “Never again.”

And when he started pulling the trigger, opponents lay scattered.

“I was getting in people’s pads and putting them on their backs,” Harlow said of his play in the last two months of the season. “A lot of it’s technique. I started coming off the ball lower and running my feet through people, just kind of being relentless in finishing off my blocks.”

Against Oregon State and UCLA last month, he was given credit by the coaching staff for 20 knockdowns in each game.

Harlow’s only regret is not making the move from defense sooner, but he never doubted himself.

” . . . I thought, ‘There’s someplace I can play and be pretty good.’ I didn’t know where, but I thought I could find a place.”

Once he found out, recognition followed. And so did pro scouts.