A year ago, Aundrey Walker was big — really big. He weighed in at 375 pounds — the heaviest of anyone on the Trojans’ roster by about 35 pounds.

The sophomore offensive tackle felt all 375 pounds, too.

“By the fifth play I would be gasping for air,” said Walker, who appeared in 11 games for USC last season.

But this spring, Walker has felt lighter than usual after shedding nearly 60 pounds during the offseason from December to March. Credit a new and improved diet filled with meats and vegetables.

“He’s completely different,” USC coach Lane Kiffin said. “When you lose 60 pounds, you move a little bit better.”

Photo courtesy of Sports Information

A more nimble Walker, who is now listed at 320 pounds, has battled junior Kevin Graf to secure the Trojans’ starting left tackle spot — a position vacated following Matt Kalil’s decision to enter the NFL draft.

For the time being, though, it appears as if the position will be occupied by Walker, who has been tasked with protecting senior quarterback Matt Barkley’s blind side.

Last week, Kiffin announced that the Cleveland native would remain at left tackle for the foreseeable future and at least for the duration of spring practice, which culminates with Saturday’s annual spring game at the Los Angeles Memorial Coliseum.

“He fits better over there with his length and his size,” said the Trojans’ third-year coach. “When you look at prototypical left tackles, that’s what they’re built like. Hopefully he can get used to it over there.”

If anything, Walker will have to get used to life on the left side, as replacing Kalil, who projects to be a top-five pick in this month’s draft, won’t be easy.

A season ago, Kalil was instrumental in paving the way for senior tailback Curtis McNeal, who ran for 1,005 yards on only 145 carries. Perhaps just as impressively, Kalil was a part of an offensive line that allowed just eight sacks all season.

Walker is aware of the challenge.

“It’s a blessing,” Walker said. “It’s a great opportunity to play left tackle after Matt Kalil. I’ve got some big shoes to fill.”

Nonetheless, through just a handful of spring workouts, Walker appears to have a solid grasp on the position following the often talked about open competition with Graf.

For the first week of spring practice, Graf started at left tackle, while Walker was inserted at right tackle. For the second week, they switched positions, and though Kiffin initially said they would rotate over the subsequent weeks, they haven’t exactly done that.

Meanwhile, Graf has taken recent events in stride.

“I’m going out there and doing what the coaches ask me as hard as I can every day — no matter where they put me,” said Graf, who started 12 games at right tackle last season. “I’m taking it one day at a time.”

Walker has said similar things.

“The goal was to help the team in any way possible and to just get on the field,” he said. “I’m still working to get better.”

Despite his left tackle frame at 6-foot-6 and 320 pounds, Walker is at left tackle full-time for the first time in his career.

A season ago, as a freshman, he was a backup on the offensive line, rotating in at a couple spots, and also played on special teams. In high school at Glenville High in Cleveland, he played right guard for a run-oriented team — contrasting the Trojans’ pro style offense, which often relies on the passing game and the left tackle as a result.

“The first day was kind of iffy,” Walker said about his new position. “Over the course of the days, I have felt more comfortable and I feel like I’m doing well.”

Similarly, Graf is adjusting to life on the right side.

“I feel comfortable at both,” Graf said. “I feel more comfortable at left, but I know I can play right tackle, too. You’re still protecting the quarterback and not letting him get hit.”

But no matter how comfortable both suggest they are on opposite ends of the offensive line, Kiffin insists the two have plenty of catching up to do, calling both tackle positions a “work in progress.”

Luckily, it’s still spring.

“I’m going to keep working,” Walker said. “Those words are motivating me to maintain the spot.”