Senators' Karlsson likely out for the season

Ottawa Senators defenseman Erik Karlsson is likely out for the rest of the season after Thursday surgery to repair his left Achilles tendon, general manager Bryan Murray said.

Karlsson, 22, suffered a 70-percent tear after being sliced by the skate of Pittsburgh Penguins' left wing Matt Cooke, while they scrapped for the puck along the boards late in the second period.

Cook's skate blade landed above the top of Karlsson's boot.

"Erik Karlsson's season is effectively over," Murray said.

The Senators will have to get by without the reigning Norris Trophy winner for at least three months. The team is already without forward Jason Spezza, who is out after having back surgery for a herniated disc.

"It's a tough blow," Senators captain Daniel Alfredsson told reporters. "Obviously, the way he's playing, and how much he means to our team, it feels terrible and I feel really bad for him."

Murray said the earliest return date in May, which allows for a possible postseason return.

"He's playing 30 minutes a game, a Norris Trophy winner, arguably the best player in the

League. It's obviously a big loss -- but like every injury, it's somebody's opportunity,"

Coach Paul MacLean said. "We have to find out who that's going to be."

Cooke wasn't called for a penalty, and called the play "a complete accident."

"I was at the end of a shift," Cooke said. "As he took a shot, I went to the corner. Him

and I were engaged and he went down screaming. I didn't even know what happened. Obviously,

I feel terrible about it. I'm not trying to do that."