Disease can cost Lars Eller NHL debut for St. Louis Blues in the coming season.
The 20-year-old great talent has been diagnosed with mononucleosis, commonly called the kissing disease.
"It was a sad message, St. Louis doctors could bring Lars after the investigation today.
We had hoped it was more innocent, "says his father, Olaf Eller, U20-national team and Hvidovre Elitehockeys coach.
"New studies will show how long it takes, but at worst it is an infection that will inhibit Lars for several months."
Lars Eller must first say goodbye to the club's camp, which starts on Sunday and could have been a springboard directly to the NHL team.
The accident was also looking for the gifted playmaker in the spring, when he was shoulder surgery and missed the World Cup in Switzerland.
Evidence suggests that Lars Eller, when the disease is over, start at St. Louis Farmer team in AHL, Peoria Rivermen.