Null, who started the last four games last season, lost a battle for the third quarterback job to Thaddeus Lewis. Ogbonnaya lost to Kenneth Darby and Keith Toston as backups to Pro Bowl running back Steven Jackson.
The Rams also waived wide receivers Danario Alexander and Brandon McRae; guards Roger Allen III and Drew Miller; linebackers Devin Bishop and Cardia Jackson; cornerback Marquis Johnson; offensive tackle Ryan McKee; fullback Dennis Morris: defensive tackle Ernest Reid; and defensive back Antoine Thompson.
Contracts of defensive end Victor Adeyanju, cornerback Quincy Butler and linebacker Bobby Carpenter were terminated. Safety Kevin Payne (knee) and T Eric Young (knee) were placed on the reserve/injured list.