The 49ers struggled on defense last season and Kelly has chosen to go in a different direction. Mangini interviewed with Kelly last week but apparently Kelly didn' t view him as a good fit.
San Francisco interviewed Houston Texans linebackers coach Mike Vrabel earlier this week and Vrabel turned down the defensive coordinator post to stick with the Texans.
The 49ers reportedly have offered the offensive coordinator position to Curtis Modkins, who is the Detroit Lions' run game coordinator.
San Francisco also reportedly has hired Derius Swinton as special teams coordinator. Swinton was a special teams assistant with the Chicago Bears.