Manusky, 43, is the primary out-of-house candidate the Chargers are considering. He served as the franchise’s linebackers coach from 2002-2006.
Former coordinator Ron Rivera became the head coach of the Carolina Panthers on Tuesdsay, creating an opening for Manusky to inherit the league’s No. 1 defense.
Under Manusky, the 49ers had the No. 13 defense in 2010, ranking sixth in rushing yards (1547) and 24th in passing yards (3697) allowed. The unit allowed 3.5 yards per carry, second-fewest in the NFL.
The 49ers are transitioning a new coaching staff after former Stanford coach Jim Harbaugh was hired last Friday. The team has reportedly granted Manusky to interview with the Chargers, Panthers, Cowboys and Cardinals.