Pittsburgh, PA (Sports Network) - Ottawa Senators defenseman Erik Karlsson suffered a cut to his left Achilles tendon during Wednesday's game against the Pittsburgh Penguins.
Late in the second period, Karlsson and Pittsburgh's Matt Cooke met along the boards while chasing down a puck, and Cooke's left skate appeared to graze Karlsson near the left ankle.
Karlsson had to be helped off the ice as he was unable to put any pressure on his left leg.
Between periods the Senators announced that Karlsson had a cut to his lower leg, but later revealed on the team's Twitter page that he suffered the laceration and will have to have surgery.
The reigning Norris Trophy winner will be out indefinitely.
Karlsson has six goals and 10 points over 14 games this season.