OTTAWA -- Erik Karlsson admits he was scared.
Four months ago, doctors removed half the ankle bone in the left leg of the Ottawa Senators defenseman during surgery to repair torn tendons.
During his recovery, doubt swirled through his head. How long would the recovery take? How effective could he be when he returned to the ice? Would he be able to maintain the same talent level that had made him the NHL's top scoring defenseman in three of the previous four seasons?
He was overcome with a sense of relief last week when he was able to return to the Senators lineup. Heading into their game against the Philadelphia Flyers on Thursday (7:30 p.m. ET; RDS2, TSN5, NBCSP, NHL.TV), he has six assists in four games and has resumed his role as the catalyst on the power play.
At the same time, he says this is a different Karlsson than we are used to seeing. He insists he has lost some of the natural skill he possessed earlier in his career. The skate laceration that tore 70 percent of the Achilles tendon in his left leg in 2013 has taken a toll, as did the foot and ankle injuries he sustained last season.
"I was worried this summer," Karlsson, 27, said. "[The ankle] didn't feel good for a very long time and I thought it was probably going to take a lot longer than it has. But those are the consequences or the risks that you take in this game sometimes. I just had to deal with it.
"But again, to have a major surgery, you wonder when and if I'll be back, and if so, will I be the same again? And then deal with it when the time comes."
Video: Karlsson causes king-sized headache for defensemen
Among the issues Karlsson has been forced to deal with is no longer being able to dominate games with the flash and flair that were the trademarks of his game.
"I don't think I'll ever be that player again," he said. "Ever since my Achilles and now this, it's not going to be the same as it used to be. I'm also a lot older and it wears on you a little bit. Even though I'm not that old.
"I think I have to come to terms with it -- I think not just me but everyone has to come to terms with that -- that you're not going to be the same guy that you were earlier in your career in the League when your body is going to feel as good as it's ever going to be. Everyone has to deal with the issue of tears and wears. It's no different for me."
While Karlsson's logic makes sense, he might have a difficult time convincing Senators coach Guy Boucher, who last week called Karlsson, "the greatest player in the world."
And it might be just as hard a sell for opponents such as the Los Angeles Kings, who watched Karlsson scoop the puck off the goal line just as center Anze Kopitar was about to put the winning goal into a seemingly empty net with 1:14 remaining in overtime at Canadian Tire Centre on Tuesday. The Senators lost 3-2 in a shootout, but Karlsson played a game-high 29:30.
In a snapshot that revealed how much opponents still respect him, Karlsson was seen laughing at the beginning of overtime when Kings players were debating who would get the job of defending him. When Kings defenseman Drew Doughty appeared to suggest that forward Dustin Brown should take that unenviable assignment, Brown gestured toward Senators defenseman Johnny Oduya as if to say: "Nah, I'll take this guy instead."
Karlsson is a two-time winner of the Norris Trophy (2012, 2015) as the NHL's top defenseman and has been runner-up for the award the past two seasons. While he believes he can be as effective a player moving forward, it will be in a different way.
Video: Erik Karlsson takes the No. 3 spot
What he may have lost in speed and acceleration, he has more than made up in hockey knowledge and how to play the game more strategically. As such, he's become selective in picking the right moments to step on the gas as opposed to always keeping the pedal to the metal like he did in his younger days.
"One thing I've learned over the years is that you can't come out too hard early in the year because it's going to get harder as you get into the season as it moves on," Karlsson said. "It's not going to be the fancy stuff on every shift any more.
"Again, that's not we're going to need to win games. That's what it's all about. When you win games you get a lot of energy. You've got to find a way to save that extra little bit for when you really need it instead of taking risks all the time."
While Karlsson was flattered by being called the best in the game by Boucher, his choice for that lofty honor is Pittsburgh Penguins center Sidney Crosby.
Karlsson knows that Crosby's injury history has caused the Penguins captain to refine his game over the years, reverting to a style where smarts and work ethic have more than compensated for the loss of the once omnipresent dynamic element in his repertoire. In that regard, Karlsson sees a lot of himself in Crosby.
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"I think you've got to find new ways to adapt your game all the time," he said. "You're never going to play the same way that you did last season or two seasons before. Things are always going to happen. It's all about managing yourself and your own body. You know what you have to do to be successful.
"Yes, [Crosby] is definitely a better player now than he was. But a lot of that has to do with experience and learning from it. You have to adapt to the situation. He's done a great job of that and I'm trying to do that too. I don't think I'm as skilled or as fast as I used to be, but at the same time I think I'm more complete.
"You know what you have to do to be successful. And you learn to find ways to make the guys around you better. That's the important thing."