Joey Bosa to miss Chargers’ opener with left foot injury

The Chargers were on the verge of getting Pro Bowl defensive end Joey Bosa back from injury.

Then he hurt himself again.

Same left foot. Different problem.

“He’s very frustrated,” coach Anthony Lynn said. “He’s been waiting for a while to get back on the field. He’s doing everything he can. He just wants to be out there with his teammates.”

Bosa will miss the Chargers’ opener Sunday against Kansas City and is now “week to week,” Lynn said, with an injury that had him wearing a walking boot Friday.

Though he wouldn’t discuss the circumstances in depth, Lynn did say Bosa’s foot is not broken.

Asked if it’s the type of injury that could linger, Lynn said: “We don’t know yet. It could be.”

Bosa, who hurt himself during a drill at Wednesday’s practice, missed all four preseason games because of an earlier foot injury.

In their official league-mandated report, the Chargers listed Bosa as having been a limited participant in the workout.

On Thursday, the team reported that Bosa did not practice at all. Friday brought the explanation for his downgraded status.

“That’s why we were being so cautious,” Lynn said. “We didn’t want anything else to happen. But it’s football. It’s unpredictable sometimes.”

Bosa’s initial injury came during an Aug. 7 practice.

But he was progressing toward being ready for the opener. At one point last month, Lynn said he “absolutely” expected Bosa to be able to play in Week 1.

Bosa left the locker room Friday wearing the walking boot. He refused a request to be interviewed.

“I was really surprised,” Lynn said. “I was looking forward to having him back, like everyone else.”

Isaac Rochell, in his second season out of Notre Dame, was projected to play a more significant role this season. Now he’ll start in Bosa’s place against the Chiefs.

The Chargers also played rookie Uchenna Nwosu and defensive tackle Damion Square, among others, in Bosa’s spot during preseason.

“It’s just kind of a title,” Rochell said of becoming a starter for the first time. “It’s not necessarily this huge new thing. But it is different. It is cool. But it’s like the same thing. I have to do what I have to do, and we all have to do our jobs.”

Rochell started all four preseason games, something he said will boost his confidence Sunday.

A seventh-round draft pick in 2017, he stuck with the Chargers as a member of the practice squad and eventually appeared in three games.

“Isaac had a great camp,” Lynn said. “He’s grown like a weed. … It’s a hell of an opportunity for him.”

Said Rochell: “It always feels good to know your coaches have faith in you. When stuff like this happens, you don’t want your coaches to feel like they’re now in survival mode.”

In 28 career games, Bosa has 23 sacks and 147 tackles. He and fellow defensive end Melvin Ingram give the Chargers two dynamic push rushers.

His loss comes as the team is preparing to face a Kansas City offense that produced 363 yards rushing in sweeping both games from the Chargers last season.

“It’s definitely tough,” cornerback Casey Hayward said. “But … with Isaac emerging, we have the utmost confidence in him to go out there and do the things he’s supposed to do. … He’s been playing well in the preseason. Now it’s time to do it in a real game.”

Gates to play

It appears the Chargers will be welcoming back Antonio Gates on Sunday.

The veteran tight end rejoined the team this week and practiced the past three days. Lynn plans to play Gates against the Chiefs.

“He looked good,” Lynn said. “Almost like he picked up where he left off. We’ll see what he can do Sunday.”

Gates, 38 and entering his 16th season, was re-signed Monday after being a free agent since last winter. Thin at tight end, the Chargers went back to a familiar face to bolster the position.

Etc.

Reports out of Kansas City indicate Chiefs safety Eric Berry will not play because of a heel injury. He is listed as doubtful. … The Chargers had wide receiver Tyrell Williams (groin) on their injury report Friday. He was a full participant in practice. … Former general manager Bobby Beathard will be inducted as the 39th member of the Chargers Hall of Fame during the game Sunday.

jeff.miller@latimes.com