Greg Manusky has agreed to a two-year contract to become San Diego's new defensive coordinator, the Chargers' official site reported on Friday.
Earlier this week, Rivera left his post in San Diego to take the head-coaching job of the rebuilding Carolina Panthers. That opened the door for Manusky, who ran the 49ers' defense from 2007-10.
Jim Harbaugh was hired as San Francisco's head coach last week, and the former Stanford coach brought over both his offensive and defensive coordinators from his time with the Cardinals with him.
That left Manusky out of a job ... but it didn't take him long to find a new home.
"I think Greg brings energy and enthusiasm and I think he will be extremely demanding and I think that gives us a chance to get better," said Chargers coach Norv Turner.
Asked what his defensive philosophy will be in San Diego, Manusky -- a former NFL linebacker -- didn't hold back.
"Hardcore. Relentless. Getting after people," he said. "(The Chargers) have in the past. Shoot, they were No. 1 last year and hopefully we'll just pick up where we were last year.
He doesn't plan on overhauling the defense, and he believes the potential is there for the Chargers to get even better on his side of the ball.
"I'm going to bring some new ideas but also continue the foundation that they've already had and just build on it. I think with the players that we have, the sky's the limit."
"He's familiar with what we do. I (like) the fact that he's been a coordinator the last four years, he's been making gameplan decisions and making game day decisions at a high level. That made him very attractive."
The Chargers also interviewed linebackers coach John Pagano and secondary coach Steve Wilks before deciding on Manusky.
"The combination of Greg and the current members of our defensive staff, (linebackers coach) John Pagano, (secondary coach) Steve Wilks and (defensive line coach) Don Johnson give us as strong a staff as I've been with and a chance to build on the good things we've done as a defensive group," Turner said.