Updated

Ottawa Senators defenseman Erik Karlsson had season-ending surgery to repair his left Achilles after the tendon was cut by a skate blade during a game against the Pittsburgh Penguins.

Senators general manager Bryan Murray said Thursday the surgery went well. He also said 70 per cent of the tendon was cut.

The Norris Trophy winner last season as the NHL's top defenseman, Karlsson was cut by the blade of Pittsburgh forward Matt Cooke's skate as the two tangled along the boards during the second period of Wednesday night's game.

The loss of Karlsson is a big one to Ottawa, which already is without star forward Jason Spezza. He is out after having back surgery for a herniated disc.