Chargers are pushing to turn one of their biggest weaknesses into a strength

The five core members of the Chargers’ 2021 secondary missed 15 games because of injury. Each was out at least two weeks.

Three of the top backups missed 29 games after getting hurt.

All those failing body parts added up to some seriously shaky moments as the Chargers’ defense too often collapsed in a 9-8 season that died just short of the playoffs.

On Saturday, the Chargers practiced with 16 defensive backs, not counting Pro Bowl safety Derwin James Jr., who remains out while negotiations continue on a potential contract extension.

The Chargers’ offseason defensive rebuild included adding quality and depth. In the back end, they signed cornerback J.C. Jackson coming off his first Pro Bowl selection and veteran Bryce Callahan, who has been lining up as the No.1 slot corner. They also drafted JT Woods, Ja’Sir Taylor and Deane Leonard.

The influx has bumped Michael Davis, who has started 49 games during the past four seasons, to fourth on the cornerback depth chart.

It also has increased the competition. Defensive coordinator Renaldo Hill said the defensive backs have brought an “urgency” to the first four days of training camp.

If any of the Chargers defenders felt too comfortable in their roles before this season, Hill suggested that possibility now is gone.

“Every rep is counting,” he said. “Maybe in the past they could have looked and said, ‘Well, I don’t have that guy behind me. I can correct it.’ But that rep may get taken away if you’re not urgent and you keep repeating the same mistake.”

Operating against Pro Bowl quarterback Justin Herbert, the defense has won most of the team periods so far.

Backup Kemon Hall intercepted Chase Daniel on Saturday in a practice that also featured pass breakups by Davis (on a 50/50 ball intended for Jalen Guyton) and Asante Samuel Jr. (on an inside screen to Mike Williams).

“Definitely happy with the progress,” Hill said.

With so many defensive backs in camp, the Chargers coaches expect the competition to only escalate as the roster is sorted out.

“It’s going to be hard for those reps to get distributed,” Hill said. “These guys know that when they’re in there, this rep matters.”

Johnson adapts

The Chargers won’t practice Sunday before returning Monday morning for their initial workout in pads.

This will be the coaches’ first opportunity to more closely evaluate first-round pick Zion Johnson, who was drafted to be the team’s starting right guard.

Rashawn Slater, who made the Pro Bowl as a rookie left tackle in 2021, praised Johnson’s confidence and noted his “calm energy.” He said the two have talked about transitioning into the NFL.

“I told him, ‘Ball is ball,’ ” Slater said. “At this level, everything moves a little bit faster. Guys have different talents, a little bit quicker and stuff like that. At the end of the day, it’s just like college. You just stay calm and trust your technique and trust what got you here. He’ll be just fine.”

The competition for the starting right tackle spot between Storm Norton and Trey Pipkins III also will intensify Monday.

So, too, will the battle for the No. 2 running back job.

“Until pads come on, I don’t think that you can make any assessment on a back,” coach Brandon Staley said. “We’re going to give them every opportunity to prove themselves. That’s what this training camp is going to be about for that position.”

The running back spots behind starter Austin Ekeler also will be determined in part by special-teams contribution. That includes fullback, where Gabe Nabers and rookie Zander Horvath are competing.

Mack’s impact

Slater called “eye-opening” what he has seen from veteran pass rusher Khalil Mack so far.

“We’re barely even rushing right now in no pads and he’s already put a couple of variations on some moves that I’ve never even seen before,” Slater said. “He’s very smart. He’s very savvy. He’s very powerful, too.”

The Chargers traded for Mack in March. Slater said battling Mack can only help bolster his game.

“I guess it just goes to show that I thought I had seen it all last year,” Slater said. “But no, there’s a lot more for me to learn, and I’m going to get a lot better going against him.”

Practice observations

• Linebacker Drue Tranquill and tight end Donald Parham Jr. did not practice Saturday because of undisclosed injuries. Staley is expected to provide updates on both players Monday.

• With James out, Tranquill and veteran Kyle Van Noy have been calling the defensive signals in the huddle.