Surgery to his right knee limited Carkner to only 29 games during the 2011-12 season. In the second game of Ottawa's first round playoff series against the New York Rangers, Carkner pummeled Rangers' forward Brian Boyle early in the first period, repeatedly punching the unwilling combatant in the face and earning a game misconduct. He received a one-game suspension for the incident. Boyle had punched Senators' star defenseman Erik Karlsson in the face during Game 1, and Carkner's actions were viewed as retribution.