The Pittsburgh Penguins announced Friday that defenseman Kris Letang will miss out least six weeks after suffering a stroke last week.
Further testing also revealed that Letang, 26, has a small hole in the wall of his heart that may have contributed to the stroke.
The condition is treatable with blood thinners and is not believed to be career threatening, the team said.
Letang has had the small hole in the wall of his heart since he was born.
He last played Jan. 27.
"Kris had one brief episode of dizziness and nausea last week," general manager Ray Shero said in a statement. "We held him out of the Los Angeles (Kings) game (Jan. 30), and when he continued to feel ill, tests conducted in Phoenix on Saturday gave us the first indication of his condition. Further testing then was conducted when he returned to Pittsburgh, and he continued to undergo a battery of tests here this week."
Letang was cleared by the team to go on vacation with his family during the NHL's Olympic break.
"I hope that by making my condition public at this time, I can help other people by encouraging them to seek medical help if they experience some of the symptoms associated with a stroke -- regardless of their age or general health," Letang said in a statement. "It obviously was a shock to get the news but I'm optimistic that I can overcome this and get back on the ice."
Shero said the team is most concerned about Letang's health.
"We're not thinking about hockey right now," Shero said. "We want to make sure he gets the best possible care and gets better. After six weeks of treatment, doctors will re-evaluate Kris."
Letang has 18 points in 34 games this season. He was a finalist for the Norris Trophy, awarded to the league's top defenseman, in 2012-13. He helped the Penguins win the Stanley Cup in 2009.
Letang has 227 points in 419 NHL games.