The 32-year-old defenseman signed with the Canadiens on July 1, 2017, getting a contract worth $4.6 million annually.
"I want to thank the Habs ownership and management for giving me an opportunity at a fresh start even though I know it wasn't necessary for them to do so, as well as signing me in the first place," Alzner said in a statement. "I'm very grateful for the friendships I've been able to forge with teammates and training staff that I'm hopeful will last a long time!
"Finally, the city for showing me a different culture and the love they have for their hockey team that is very admirable. I'm looking forward to hopefully getting another chance to play in the League and walk into the Bell Centre again."
After playing in 82 games in his first season with Montreal, Alzner had one assist in 13 games the past two seasons. He played most of that time for Laval of the American Hockey League and scored 19 points (two goals, 17 assists) in 87 games.
Alzner will become an unrestricted free agent when the signing period begins Oct. 9.
Selected by the Washington Capitals in the first round (No. 5) of the 2007 NHL Draft, Alzner has scored 130 points (20 goals, 110 assists) in 686 regular-season games with the Canadiens and Capitals and 11 points (three goals, eight assists) in 64 Stanley Cup Playoff games.
