The team announced the deal with the former first-round pick for Baltimore on Thursday. Boller will be added to the quarterback mix with former No. 1 overall pick JaMarcus Russell, Bruce Gradkowski and Charlie Frye.
Boller never lived up to the billing after being drafted 19th overall by Baltimore in 2003. The former Cal star has made 46 starts in his career, throwing 50 interceptions and only 48 touchdown passes. His career passer rating is 70.6.
Boller spent one year in Baltimore with new Raiders offensive coordinator Hue Jackson. But he did not play in the 2008 season because of a shoulder injury.
Boller played in seven games last season for St. Louis