SAN DIEGO -- With inside linebacker Manti Te'o ruled out for this week’s contest against San Francisco because of a sprained left foot, the San Diego Chargers will use a rotation of players to replace the Notre Dame product.

Sixth-year pro Reggie Walker is listed as Te’o’s backup on the team’s unofficial depth chart and will see time next to Donald Butler with the starters. But depending on what personnel grouping defensive coordinator John Pagano employs, free-agent addition inside linebacker Kavell Conner should see time with the starters as well.

Butler said it’s good to have experienced players to fill in for the injured Te’o.

“It’s huge,” Butler said. “It’s not a drop off at all. It’s a next-man-up mentality, and they’ve come in and have done well these last couple days.”

Walker is Mr. Versatility for Pagano’s defense. He can play all four linebacker positions for the Chargers. Signed after final roster cuts last season, Walker, 27, started six games for San Diego in his first year with the team. In 451 snaps, he finished with 42 tackles -- including five tackles for loss -- and three sacks.

“It’s valuable to have a guy like that,” Pagano said. “Any time you’re in a backup role and can come in and start games for you, it’s a plus.”

Conner, 27, signed with the Chargers during free agency this past offseason. He started 36 games during his four years in Indianapolis. Conner’s best season was 2011, when he started 15 games, finishing with 104 tackles. Conner also had 13 special-teams tackles for the Colts in 2013.

“It’s a great pickup for us, knowing his positional flexibility, not only as a linebacker but his position on special teams,” Chargers head coach Mike McCoy said about Conner. “He’s a veteran who has played plenty of snaps and has been there before. He’s been a leader on special teams from the very first day that he was here.”

Conner said he’s working to master San Diego’s defense.

“I’m still learning, honestly,” Conner said. “I’m trying to get everything down, learning some of the nuances of the defense and trying to get better every day.”

Pagano said Te’o had been playing well before the foot injury. Through two preseason games, Te’o leads the team in tackles with 11.

“He’s been doing really well,” Pagano said about Te’o. “You see the instincts. You see him a lot more comfortable just being able to go out, down in and down out just playing the game, reading things and seeing things. Everything slowed down for him.

“I think one of his key moments was when he saw that screen in the Dallas game, the way he was able to read it and react to it. He has great instincts, and you see it out here on the practice field.”

Te’o missed most of the exhibition season and three regular-season games because of a sprained right foot last year. He played the rest of the season with the injury but needed surgery after the 2013 season was over to repair a fractured bone in his foot.

Te’o injured his left foot this time and was seen wearing a boot after practice to protect the injury. However, Te’o is not expected to be out for an extended period of time.

“I’m just being patient with it, being smart,” Te’o said. “You have to just let your body heal.”