It’s been four months since Aaron Donald announced his retirement but the official transaction was not completed until Friday when the Rams placed the future Hall of Famer on the NFL’s reserve/retired list.

Although Donald is not at training camp at Loyola Marymount, his influence is felt daily, defensive coordinator Chris Shula said.

“We see him all the time on tape, and we talk about it a lot,” Shula said after a jog-through. “But obviously, we’re moving forward with the guys we have here and trying to build the best defense we can.”

With an offense that features quarterback Matthew Stafford, receivers Cooper Kupp and Puka Nacua, running back Kyren Williams and an experienced and upgraded line, the offense is not a question mark for the Rams.

The defense, however, is no longer a known quantity.

Shula, 38, is in his first season as coordinator after working as a defensive position coach for seven seasons on coach Sean McVay’s staff.

Shula worked under former Rams coordinators Wade Phillips, Brandon Staley and Raheem Morris, helping the Rams to five playoff appearances, two Super Bowls and one championship.

McVay promoted Shula after Raheem Morris left to become coach of the Atlanta Falcons.

“You’re always going to put your personality on the defense,” Shula said. “Obviously, I can’t be Raheem Morris. I couldn’t even try to be Raheem Morris, I don’t think anybody could.

“But I’m going to try and take aspects just from my past and stuff I’ve believed in. … It’s about the players. It’s about finding out what these guys can do, and what these guys are good at, and then kind of molding it to that.”

Less than a week into training camp, Shula and a defense led by linebacker Ernest Jones IV already is being tested.

Reserve cornerback Derion Kendrick suffered a season-ending knee injury on the first day of practice, and starting cornerback Darious Williams suffered a hamstring injury Thursday.

Williams did not participate in a jog-through Friday. Shula referred a question about his injury to McVay, who did not speak to reporters Friday but will address the issue Saturday.

Rams defensive back Tre’Davious White has looked healthy in camp.

(Robert Gauthier/Los Angeles Times)

Cobie Durant, Tre Tomlinson, Josh Wallace and Charles Woods will get extended reps with starter Tre’Davious White, who appears ahead of schedule in his comeback from Achilles surgery.

Tackle Kobie Turner participated in the jog-through on Friday, but the second-year pro has yet to take part in a full practice because of what McVay has described as a groin issue.

Turner, who was voted to the NFL’s All-Rookie team last season, is regarded as a player who can lead the line.

“He doesn’t have to replace Aaron Donald,” Shula said. “He doesn’t have to be Aaron Donald. He just needs to be Kobie Turner.”

The Rams also are counting on young players to step up.

They selected edge rusher Jared Verse in the first round of the NFL draft, and then traded up to select tackle Braden Fiske, Verse’s Florida State teammate, in the second round.

The two rookies have “a long way to go” and “a lot to clean up,” Shula said. But they are demonstrating the characteristics that attracted the Rams.

“You see a lot of the flashes,” Shula said. “You see the aggression, you see the attacking mindset, you see the style of play they had at Florida State and exactly why we picked them where we did.”

McVay and offensive coordinator Mike LaFleur have proven players at nearly every position, most importantly Stafford.

The Rams avoided a major distraction on the eve of camp by finally agreeing to adjust the 16th-year pro’s contract.

Stafford has looked sharp.

“He looks like No. 9,” LaFleur said. “He looks like he can go as long as he wants. Hopefully that’s a long time.”

Unlike last year’s training camp, Kupp is at full speed. After a record-setting rookie season, Nacua knows the ins and outs of the offense. Veteran receiver Demarcus Robinson also has a full season of experience in McVay’s scheme.

Williams sat out nearly all offseason workouts because of a foot injury, but he appears to be at full strength. Rookie running back Blake Corum also has impressed.

Steve Avila is transitioning from left guard to center, and tight ends Colby Parkinson, Davis Allen and Hunter Long are attempting to show they can make up for the on-field absence of Tyler Higbee, who is recovering from knee surgery.