Seidenberg's expected recovery time will be six to eight months.
Seidenberg suffered the injury late in the third period during Boston's 5-0 win over the Ottawa Senators Friday night at TD Garden. He left the game with just under five minutes to play in regulation after he was tangled up behind the Boston net with the Senators' Cory Conacher.
After the collision, Seidenberg remained on the ice for a moment, grabbing his right knee before skating off on his own and going to the locker room. He did not return and finished with 18:45 of ice time.
Seidenberg did not accompany the team to Ottawa, and neither did forward Carl Soderberg, who remained in Boston to be evaluated for an undisclosed injury suffered in Friday's win. On Saturday morning, the Bruins announced they had recalled defenseman David Warsofsky and forward Nick Johnson from their AHL affiliate in Providence.
Meanwhile, Bruins captain Zdeno Chara will not play in Saturday night's game due to injury, the team announced. The defenseman is day to day.
The Bruins recalled defenseman Zach Trotman from Providence of the AHL on an emergency basis and sent down goaltender Niklas Svedberg. Trotman is eligible to play for the Bruins Saturday night in Ottawa.
Seidenberg, 32, signed a four-year deal worth $13 million at the start of this season.