SAN JOSE -- Erik Karlsson won't play in the Sharks' games for the remainder of the week, coach Peter DeBoer said at the team's practice facility on Thursday.
"We're waiting on some test results and things like that," DeBoer said of the All-Star defenseman. "I think it is [his groin], but I don't have all the stuff yet."
Karlsson left in the second period of San Jose's 4-1 loss to the Boston Bruins on Tuesday. As he tried to defend Boston defenseman Charlie McAvoy, Karlsson fell awkwardly and headed to the Sharks' dressing room.
The two-time Norris Trophy winner briefly returned in the period, but did not see the ice in the third. He had left Saturday's loss to the Columbus Blue Jackets after aggravating a groin injury that caused him to miss nine games spanning the All-Star break.
Karlsson told DeBoer he was good to return on Tuesday after missing one game. On Thursday, DeBoer chalked up Karlsson's injury to poor circumstances rather than poor planning.
"I think everybody acted appropriately in getting him back in," DeBoer said, "including the player and the medical team. We had a couple of unfortunate situations, so we'll go from there."
Karlsson, a two-time Norris Trophy winner, has scored 45 points in 52 games in his first season in San Jose. By absolute or relative share of 5-on-5 shots, attempts, and chances, Karlsson has been one of the NHL's most effective defensemen this season, and the Sharks have been one of the league's best puck-possession teams.
The Sharks have played well without Karlsson, but they'll need him as the regular season winds down. A rematch with the Vegas Golden Knights in the first round of the Stanley Cup Playoffs looks possible, if not likely, and that series would be far more daunting for San Jose sans Karlsson.
DeBoer said the Sharks are thinking of the bigger picture when it comes to Karlsson's health. He said they will be "over-cautious" working him back in, but shot down the possibility of shutting him down until the postseason.
"We're going to hold him out until we don't have to," DeBoer said, "but we can't put this guy in a bubble and roll him out the first playoff game. He's gotta play games when he's healthy enough to play games."
That won't be Friday against the Colorado Avalanche or Sunday against the Chicago Blackhawks at SAP Center. After that, the Sharks don't play again until next Thursday, when they host the Montreal Canadiens.
Whether Karlsson suits up then, or even later, DeBoer trusts the defenseman won't be taking an unnecessary risk.
"This isn't a guy who recklessly got out there because he just wanted to play," DeBoer said. "He knows the big picture. He knows where we're trying to go here. I think there were just some circumstances."