Karlsson, 27, led Ottawa with 18 points (two goals, 16 assists) in the playoffs, helping the Senators reach the Eastern Conference Final, where they were eliminated in seven games by the Stanley Cup champion Pittsburgh Penguins.
He also revealed after the Eastern Conference First Round that he had two hairline fractures in his left heel sustained blocking a shot during the regular season. Dorion also said Karlsson had muscle damage in his ankle.
"I'm not a surgeon. All I know is the two cracks, there's a chance they caused the tendons to tear and the pain because of that was excruciating," Dorion said.
"So for Erik to play with that type of pain, not even close to be being 100 percent, if you know anything about tendons and trying to skate, for him to play at that level, that tells me, 'wow, if he can play at that level on one leg, imagine when he's going to be healthy and really wants to go at it, how good he can be?'"
The Senators captain had 71 points (17 goals, 54 assists) in 77 games and is a finalist for the Norris Trophy as the NHL's top defenseman for the fourth time. He won the award in 2012 and 2015.
"It just tells us we have something special in Erik in Ottawa and we hope he's going to be here for his whole life," Dorion said. "It just shows how good a leader he has become and how good of a player he is."
