Ottawa GM Bryan Murray announced Thursday that Erik Karlsson is expected to miss three to four months after he underwent surgery to repair a 70-percent tear in his Achilles. His absence will leave a gaping hole on the team's blueline. Karlsson had been averaging 27:03 of ice time per game this season. The Senators defenseman and reigning Norris Trophy winner was off to a strong start with six goals, 10 points and a plus-6 rating in 14 games. He is also the NHL shot leader with a whopping total of 63.