Former San Francisco 49ers head coach Mike Singletary is joining the Vikings coaching staff as Linebackers Coach/Assistant Head Coach.  Singletary was fired with 1 game left this season as head coach of the 49ers.  Singletary and Viking head coach Leslie Frazier were teammates with the Chicago Bears in the 1980s.  The Vikings also interviewed Atlanta Falcon quarterback coach Bill Musgrave Tuesday for their offensive coordinator position.  Possible offensive coordinator option Josh McDaniels agreed to a contract to be the offensive coordinator for the St. Louis Rams.