"It's a version of the same injury," DeBoer said after the latest medical tests on the 28-year-old defenseman. "I don't anticipate it being long term. No surgery, nothing like that. But we're going to be obviously extra cautious and make sure."
Karlsson missed his second straight game when the Sharks defeated the Chicago Blackhawks 5-2 on Sunday.
The two-time Norris Trophy winner, who has 45 points (three goals, 42 assists) in 52 games, missed nine straight games from Jan. 19-Feb. 14 because of the groin injury. He returned to the lineup on Feb. 16 against the Vancouver Canucks and was in the lineup for four straight games but re-injured his groin Feb. 23 against the Columbus Blue Jackets.
After missing the next game, Karlsson returned Feb. 26 against the Boston Bruins but re-aggravated the injury again. That setback led to the latest medical tests.
"No surgery," DeBoer said. "It's going to get better. It's just time, so that's good news."
In 14 games Karlsson has not played this season (12 injury, two suspension), San Jose is 10-3-1.
The Sharks are in second place in the Pacific Division, three points behind the first-place Calgary Flames and nine points ahead of the third-place Vegas Golden Knights.