Source: Raiders interview Manusky

Dennis Allen’s coaching staff with the Oakland Raiders continues to take shape.

A source told FOXSports.com that running backs coach Kelly Skipper will be retained and Greg Manusky was interviewed for the defensive coordinator position. NFL Network reported Greg Knapp also has accepted the offensive coordinator position that, as first reported by FOXSports.com, was offered to him several days ago.

Manusky served as San Diego’s defensive coordinator in 2010 but was fired at the end of the season. Chargers head coach Norv Turner cited a desire to improve San Diego’s third-down defense as one of the reasons for the change.

Manusky served as San Francisco’s defensive coordinator from 2007 to 2010.

Chuck Bresnahan was Oakland’s defensive coordinator last year under head coach Hue Jackson, who was fired at season’s end. Bresnahan’s future with the Raiders also is in serious doubt.

ESPN reported that the Raiders were denied permission to interview Denver Broncos linebackers coach Richard Smith for their defensive coordinator spot. Allen was Denver’s defensive coordinator last season before being hired last week by the Raiders.

Skipper has spent the past five years on Oakland’s staff, including the past three as running backs coach.

Knapp spent last season as Houston’s quarterbacks coach. He previously served as Oakland’s offensive coordinator in 2007 and 2008 and held the same position with San Francisco (2001 to 2003), Atlanta (2004 to 2006) and Seattle (2010).