On July 1, 2012, Methot was traded to the Ottawa Senators in exchange for forward Nick Foligno. Ottawa had reportedly on multiple occasions attempted to acquire the defenceman during the 2011–12 season, but were unable to finalize the transaction. The loss of two of Ottawa's starting six defencemen via free-agency meant that acquiring a defenceman became a major priority, and the team again set their sights on Methot, an Ottawa native. After starting the season paired with Norris Trophy-winning defenceman Erik Karlsson, Methot was charged with the responsibility on anchoring the team's defense after his partner was lost to an Achilles injury. The Senators finished the year with the NHL's second-lowest goals against average (GAA) as a team, and Methot's steady play led to an invite to Team Canada's training camp in the summer of 2013 in preparation for the 2014 Winter Olympics, though he was not ultimately selected for the final roster.