American BMX racer Connor Fields is awake, stable and awaiting further medical evaluation at the hospital, according to statement issued U.S. Olympic and Paralympic Committee chief medical officer Dr. Jon Finnoff.
Fields was injured in a violent crash on the first lap of his qualifying heat the Tokyo Olympics. The reigning gold medalist slammed into the turn coming off a jump and was hit by two other riders.
Medical personnel raced onto the course to attend to him before carrying him away on a stretcher to an ambulance at Ariake Urban Sports Park.
The 28-year-old from Las Vegas qualified for the finals despite the crash, but was not able to race.
Dutch rider Niek Kimmann won gold in the event.
"I haven't seen the crash, but I hope he's OK," Kimmann said. "He's been a great ambassador for the sport. For me, it's sad he wasn't able to defend his gold medal."
Australia's Saya Sakakibara also crashed out of the semi-finals. The Olympics acknowledged both racers' crashes in a tweet.