CSN Bay Area

Coach Jim Tomsula officially added a key component to his defensive coaching staff on Wednesday with the hiring of ex-Raiders defensive coordinator Jason Tarver, CSNBayArea.com confirmed.

Tarver was hired as senior defensive assistant/linebackers coach. The 49ers have yet to hire a defensive coordinator, but the source said Tarver will have some say on calls and game-planning.

[MAIOCCO: Tomsula brings back long-time Holmgren aide]

Tarver, 40, held the defensive coordinator position in Oakland for the past three seasons. Former Raiders coach Dennis Allen, who hired Tarver in 2012, may have had a chance to join the 49ers' staff. Rather than waiting for the 49ers, Allen accepted a position on Sean Payton's staff this week as senior defensive assistant. Tarver's new title with the 49ers was first reported by ESPN.

A source confirmed Eric Mangini, who was released from his contract last week as 49ers tight ends coach, is a known candidate for the 49ers' defensive coordinator position. Mangini reportedly interviewed with new Raiders coach Jack Del Rio for the same position. Mangini, the former New York Jets and Cleveland Browns head coach, has a defensive background. But he joined Jim Harbaugh's staff in 2013 as an offensive assistant.

The Cincinnati Bengals denied the 49ers' request to interview former 49ers defensive backs coach Vance Joseph to become assistant head coach/defensive coordinator, the Denver Post reported. Joseph, the Bengals' defensive backs coach, worked was a member of the 49ers' coaching staff from 2005 to 2010. Joseph worked with Tomsula and Tarver.

Tarver spent 10 seasons as a 49ers assistant coach under Steve Mariucci, Dennis Erickson, Mike Nolan and Mike Singletary. He served his final six seasons with the 49ers as outside linebackers, where he worked closely with Tomsula, the defensive line coach, for four seasons.

He spend the 2011 season coaching at Stanford as the defensive coordinator and linebackers coach before returning to the NFL with the Raiders in 2012.