Karlsson hasn't played since sustaining a 70-percent tear of the Achilles' tendon in his left leg when he was stepped on by the Pittsburgh Penguins' Matt Cooke during a game Feb. 13.
The 2012 Norris Trophy winner underwent surgery to repair the cut Feb. 14, and was expected to miss 3-4 months. He had 10 points in 14 games at the time of the injury, and was averaging 27:03 of ice time per game.
This team has been a real treat to say you've been the head coach of them. I'm extremely proud of this group ... after the disappointment of (the Game 6 loss) is digested, it's always a lot easier as a coach when your team has emptied its tank, and that team emptied its tank for me for three months.
— Senators coach Dave Cameron after getting eliminated in the first round by the Canadiens