Police in Quebec City initally told Radio-Canada that the man had succumbed to his injuries, but a release issued by the Centre hospitalier universitaire de Québec Wednesday morning said that he remains in critical condition.
The man was at a private party in the Beauport area celebrating the St-Jean-Baptiste long weekend early Monday morning when he fell off the moving vehicle.
Quebec City newspaper Le Soleil reported the 21-year-old played for the Limoilou Titans college basketball team and was poised to become assistant coach in the upcoming season.
Police have not confirmed that the accident was the result of so-called car surfing, a dangerous stunt that involves trying to balance on top of a moving car.
The driver of the vehicle, a 19-year-old man, was charged with hit and run and criminal negligence causing bodily harm on Tuesday.
The accused was held in custody pending a bail hearing, expected to take place Wednesday.