Hungary international Zoltán Horváth was killed in a car accident in the early hours of Monday.
The 30-year-old Falco KC Zzombathely center was driving to Szombathely from Sopron when he lost control of his car on an icy surface and had a head-on collision with a truck.
Horváth was taken to hospital and doctors were unable to save him.
The driver of the truck is in hospital with severe injuries.
Horváth, who was married, played in all six of Hungary's Division A Relegation Round games this year and averaged more than 24 minutes per contest as the Hungarians avoided the drop to Division B with a 4-2 record.
In Hungary's top flight, Horváth averaged more than 21 points and 10 rebounds per game for Szombathely.
"It's a real tragedy," Falco coach Nikola Lazic said on the team's official website.
"There is no explanation. It is very difficult to say anything now.
"He was a young, talented, good basketball player and a great man has left us here...
"The team has lost one of its best players. He cannot be replaced."
Mészáros Lajos, the national team coach, said he and his players had been left stunned.
"The sport has lost a brilliant, tremendously dedicated, smart and intelligent person," Mészáros said on the Hungarian Basketball Federation website.
"He arrived relatively late in the squad but made an immediate impact."