He was injured in the third period Friday night when he became entangled with Ottawa forward Cory Conacher behind the Bruins' goal.
Seidenberg tore his anterior cruciate ligament and medial collateral ligament in his right knee. General manager Peter Chiarelli said in a statement Saturday the expected recovery is six to eight months.
Seidenberg has a goal and nine assists in 34 games this season. During his career, he has also played for Philadelphia, Phoenix, Carolina and Florida.
Copyright 2014 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.