Kostitsyn, 23, posted 18 points (seven goals, 11 assists) in 47 contests during his third season in the NHL with Montreal last year. In 155 career NHL games, the 6-foot, 210-pound left winger has racked up 24 goals and 44 assists.
Kostitsyn played for the Habs in each of their last three playoff appearances, putting up eight points (three goals, five assists) in 18 games.
He was also the subject of controversy over his attitude and work habits. Kostitsyn was suspended after refusing to report to the minor leagues in October and was told by the Canadiens to stay away from the team prior to Game 4 of their Eastern Conference Finals series against Pittsburgh.
The Belarus native played for his country at the 2010 Vancouver Olympics, leading the team with five points in four games.