Miro Heiskanen diagnosed with mononucleosis

Dallas Stars defenseman Miro Heiskanen has been diagnosed with mononucleosis, according to the Stars PR.

He will be out indefinitely as he recovers and has been placed on injured reserve by the team.

Mononucleosis, more commonly known as “mono,” is a viral infection that causes sore throats and fever, as well as extreme fatigue. It usually takes several weeks to fully recover from it and doesn’t need much treatment aside from rest.

It’s a massive blow to the Stars, who are currently in the midst of a playoff push and had a four-game winning streak before losing 2-1 on Tuesday to the Nashville Predators. Dallas currently sits in the second wildcard spot in the Western Conference, with a 32-21-3 record and 67 points, one more than the Edmonton Oilers with a game in hand.

Heiskanen is obviously a massive part of the Stars’ success, logging almost 25 minutes a game and putting up 29 points in 52 games this season. He’s also been really strong defensively, with a 52.25% CF% and 56.35% xGF% this season.

Heiskanen is in his fourth season in the NHL and his first with his new eight-year contract at an $8.45-million AAV.