As per club policy, financial terms of the deal were not disclosed.
The 26-year-old Kostitsyn ranked fourth on the team in scoring and third in goals during the 2010-11 season. He finished with 45 points on 20 goals and 25 assists in 81 games.
The Canadiens selected Kostitsyn with the 10th overall pick in the 2003 NHL Entry Draft.
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