USC linebacker Lamar Dawson is impressing in workouts

Linebacker Lamar Dawson is back in the middle of activity on USC’s practice field.

It has been 17 months since Dawson, a three-year starter, suffered a knee injury that ended his 2013 season and sidelined him in 2014.

But the senior from Kentucky has been one of the pleasant surprises of USC’s first two spring workouts.

“It’s been awhile since I’ve been on the field,” he said Thursday, “so I’m glad to turn people’s heads when I’m back on.”

A physically sound Dawson would be a welcome addition to a USC defense that must replace All-American defensive tackle Leonard Williams and linebacker Hayes Pullard, a four-year starter.

The 6-foot-1, 230-pound Dawson emerged as a starter in the final four games of his freshman season in 2011.

He suffered a knee injury during practice in October 2013 and had surgery the next month.

Dawson attempted to come back last season, but never appeared fully healed.

“My recovery was a slow process,” he said. “I just wasn’t ready last year.”

Dawson has moved well, without a knee brace, during two no-pads workouts. The Trojans will be in shoulder pads Saturday and in full pads several times during the spring.

“When we get the pads on, we’ll see how my body feels then,” he said.

Linebackers coach Peter Sirmon expects Dawson to be especially effective against the run.

“He’s real smooth in the box,” Sirmon said. “I like the way he stays square on blocks, he’s got good vision. He’s a natural inside backer.”

Dawson and senior Anthony Sarao, who will be sidelined for spring practice because of a foot injury, provide a veteran presence in a linebacker corps that will add four talented freshmen for the 2015 season. Cameron Smith is participating in spring practice and Osa Masina, Porter Gustin and John Houston will arrive during summer.

Sirmon said he was looking for production from whoever replaces Pullard, the Trojans’ leading tackler in three of his four seasons.

“You hear a lot of chatter, you know, ‘You need a quarterback on the field,’” Sirmon said. “Man, I want a guy that makes tackles.”

Filling a void

Senior defensive lineman Delvon Simmons is confident that he and teammates in his position group will make up for the departure of Williams, who could be among the top five players selected in the NFL draft.

“It was a big loss,” Simmons said. “We have a good group of guys that are more than capable to step in and fill the roles that need to be filled.”

Simmons, 6-5 and 295 pounds, played last season after transferring to USC from Texas Tech in 2013. He made 44 tackles, including 2 1/2 for losses.

Simmons said he learned from Williams, nose tackle Antwaun Woods and other linemen last season.

Now he is more experienced and comfortable in the system.

“I feel like it’s a progression,” Simmons said. “I made some strides.”

Quick hits

Adoree’ Jackson, who spent all of Tuesday’s opening practice on defense, played receiver Thursday. Coach Steve Sarkisian said the sophomore would continue to alternate the next four workouts…. Sarkisian said there was no update on tight end Bryce Dixon, who remains absent because of what Sarkisian has described as a student-conduct issue…. Sarkisian said Sarao has a small fracture in his foot. “We just want to make sure it heals properly so that when August rolls around he’s just 100% and not dealing with the thing,” he said.… Charles Burks, a linebacker who had a season of eligibility remaining, has graduated and will transfer to play elsewhere, Sarkisian said.

Follow Gary Klein on Twitter @latimesklein