Bristol Motor Speedway said Kyle Busch was hit in the chest before he confronted a fan on his way to his motor home following the NASCAR Cup Series race Saturday night.
Video of the incident has made the rounds on social media and shows Busch getting off his golf kart and chest-to-chest with the fan, who then shoved Busch. They were separated by Busch's representatives and an officer of the local sheriff's department.
A Busch spokesman said the driver had no comment, but the track indicated that Busch tried to ignore the fan until being struck by him.
"Our security team has investigated a post-race incident where a guest repeatedly confronted Kyle Busch verbally and physically while he was signing autographs for fans," the BMS statement said. "As Busch then prepared to leave in his golf cart, the individual struck the driver across the chest, and at that time, Busch confronted the individual.
"The two were separated quickly, and a uniformed officer pulled the individual to the side, allowing Busch to depart."
No one was arrested, according to the Sullivan County Sheriff's Office and the Bristol Police Department.
Bristol is one of the few tracks where drivers must walk through a tunnel to outside the grandstands, where they often get in golf karts to be driven to their motorhomes. Fans who are also in the infield can use the tunnel at the same time as the drivers, and those fans with grandstand tickets often line the fence by the tunnel looking for autographs.
"Bristol Motor Speedway appreciates the fan accessibility provided by NASCAR drivers, and we will work to ensure that fans and drivers continue to have great experiences together at BMS," the track statement said.
Busch is a polarizing figure on the track, and he had an incident during the race in which he spun Martin Truex Jr., enraging some fans.
Busch is a member of the NASCAR Cup Series drivers council, which regularly meets with NASCAR about issues in the sport, including security.