Radim Simek will be out indefinitely for the San Jose Sharks because of a knee injury.
The 26-year-old rookie defenseman, who had been playing on the first pair with Brent Burns, will have surgery to repair damage to the anterior cruciate and medial collateral ligaments in his right knee after being injured during the first period of San Jose's 5-4 win at the Winnipeg Jets on Tuesday. Jets forward Andrew Copp fell on Simek's right leg, and he had to be helped off the ice.
General manager Doug Wilson said there is no timetable for Simek's return.
"It's unfortunate," Sharks coach Peter DeBoer said Thursday. "He played really well. I really liked the element he brought for us physically and how decisive he was. He did a good job. It's on the guys that go into those spots to keep some of those elements in their game because I thought it really helped us.
"The good news is we're eight, nine deep in the organization in defensemen. I know when we sat at the [NHL Trade} deadline we talked that we're probably going to need all eight or nine defensemen at one point or another if we get where we want to go."
Simek, signed by the Sharks as a free agent on May 23, 2017, had 27 points (seven goals, 20 assists) in 67 games with San Jose of the American Hockey League last season. He became a regular with the Sharks in early December and has nine points (one goal, eight assists) and a plus-7 rating in 41 games this season, averaging 15:13 of ice time.
San Jose, which hosts the Florida Panthers at SAP Center on Thursday (10:30 p.m. ET; NBCSCA, FS-F, NHL.TV) is already without defenseman Erik Karlsson, who has been out since re-aggravating a groin injury in a 4-1 loss at the Boston Bruins on Feb. 26.
Karlsson told The Athletic on March 8 he would be back for the start of the Stanley Cup Playoffs in April but wasn't sure if he would play again during the regular season.
Defenseman Joakim Ryan is expected to replace Simek on the Sharks first pair against the Panthers. The 25-year-old, who has five assists in 34 games for the Sharks this season, has not played since Jan. 22. He has 17 points (three goals, 14 assists) in 96 games through two NHL seasons with San Jose.
"He's an experienced guy," DeBoer said of Ryan. "He sat and watched for a while. He knows what we need out of him. He's capable of doing it. Now he's got to come in and get it done.
"My expectations are high. We don't have time at this time of year for guys to work their way into the lineup. The guys who have preceded him in these situations, [defenseman] Dylan DeMelo, Simek when he jumped in after sitting for that long, jumped in and grabbed a job. I'm not lowering that bar for him."
Ryan said he is ready to step into a role playing alongside Burns or whatever role San Jose asks of him.
"I feel like I'm prepared well," he said. "I've been working in these skates here. When you're not playing you're doing extra work, so my conditioning feels great. ... Just try to keep things simple at first. Be aggressive and try to take the body as much as possible and try to get into the game the first 10 minutes and just see how it goes from there."
San Jose (43-19-8) is in first place in the Pacific Division and Western Conference, one point ahead of the Calgary Flames.
NHL.com correspondent Eric Gilmore contributed to this report