Karlsson suffered a 70 per-cent tear to his Achilles February 13th in a game against Pittsburgh Penguins when Penguins forward Matt Cooke stepped on the back of Karlsson's leg.
Karlsson was expected to miss the remainder of the season following the injury, but his return now seems like a real possibility.
The 22-year-old took part in practice drills and didn't seem to be showing any signs of discomfort.
"Even if it wasn't the hardest practice in the world it was still a good thing to do and it gave me some perspective on where I am right now," Karlsson said. "There's not a timeline. I don't think anyone expects anything more than trying to skate as much as possible and getting that normal feeling back in my leg again and the more I skate the better off I'm going to feel.
"When the time comes it's probably going to be a decision that's going to be made the same day."
While the Senators would love nothing more than to have the defending Norris Trophy winner back in the lineup, Karlsson said he wouldn't rush his return.
"Every injured player wants to get back as quick as possible, but I'm not going to put myself in a situation where I don't feel comfortable and I'm not going to jeopardize anything going into next season and I'm not going to make any stupid decisions," he said. "I don't think anyone working around me either is going to give me any bad advice and we just have to wait and see how it feels going forward practising with the team."
Karlsson was estimated to be out a minimum of three to four months after surgery, and as many as five to six.
Friday made exactly nine weeks since he underwent surgery and it wouldn't be a stretch to say that few would have expected him to be back on skates at this point, let alone taking part in practice.
"I think early in my injury it was tough to say how it was going to go and I couldn't really do much, but I think the last couple of weeks it’s been progressing every day and even though it's very small things it still feels better and more normal and everything is starting to work more," Karlsson said. "That's why it's so tough to set a timetable because I don't think anyone has been around this type of injury before either, so it's just going to be day-to-day and as long as I keep feeling better and not worse it's a good thing.
"If I wake up tomorrow and it feels as it today or better it's a good sign. It shows that I can keep doing what I'm doing and just push forward."
While it would be easy to picture Karlsson back in action, expectations should be tempered as he has yet to take any kind of contact or take part in a rigorous practice. Karlsson himself alluded to the fact that he has to clear those challenges first.
"One thing is going to be to go down in the corners and get the pucks and have a guy on you," he said. "Those small movements that get you out of the way every once in a while and just the timing of it all I think that’s going to be the key. The more I practise and the more drills I do I'll have a better sense of how I feel and today was just the first day and I felt pretty good being out there and moving pretty well, but obviously it doesn't feel like it used to."
Even if he were to return, it could take a while before he becomes the player he was prior to the injury.
"I don't have any pain or anything like that which is good," he said. "It's not connecting as well as I want to and I might not be as fast as I want to either and that's something that I'm going to have to work with and maybe change the game a little bit for the start when I start playing, whether it's this year or next year. It's probably going to be a while before I feel 100 per cent again."
His teammates say he doesn't look too far off form coming back.
"I hope he comes back soon and he's going to be a huge help for us," said defenceman Marc Methot. "He looked pretty fluid in his movement and in his skating and he didn't look to show too many weaknesses so that was promising. I guess now it comes down to contact and getting in shape."
Senators' owner Eugene Melnyk was at practice and admitted to being shocked by Karlsson's progress.
"I'm stunned," Melnyk said. "The healing has been extraordinary, it's almost unheard of, but he's a special person and he's worked hard to get back and he wants to get back and he wants to contribute. We're excited at the thought he could come back."
Melnyk was extremely vocal following the injury and was extremely disappointed when the league chose not to discipline Cooke, but he chose to bite his tongue Friday.
"I've committed to not saying anything about it until we've completed everything we need to do and speak to the league about it," Melnyk said. "I'll do anything I have to do to protect my players. It's as simple as that and that's exactly what I'm doing."
Melnyk is working with forensic doctors to prove that Karlsson's injury was no accident and he is awaiting the results from the investigation.