Three-time NASCAR Sprint Cup champion Tony Stewart has been hospitalised with back injuries after an accident on an all-terrain vehicle.
Stewart suffered the injury in a non-racing incident and was awake, alert and able to move his extremities according to a statement from his Stewart-Haas Racing team.
Spokesman Mike Arning said Stewart was injured on Sunday on the West Coast of the United States.
Report suggest Stewart flipped a sand buggy outside of San Diego and was airlifted to the hospital.
"We have received word from Stewart-Haas Racing of Tony Stewart's accident and injury," NASCAR chairman Brian France said.
"On behalf of everyone at NASCAR, I wish Tony a full recovery and look forward to seeing him back in our sport when he's ready to return."
Further updates on Stewart's condition are not expected until Thursday, according to Arning.
Stewart is due to begin his final season of NASCAR competition with Daytona 500 practice next week.
The injury is the latest in a long line of traumas for the 44-year-old, who is the only driver to win series championships in both IndyCar (1997 Indy Racing League) and NASCAR Sprint Cup (2002, '05 and '11).
Stewart broke two bones in his right leg in August 2013 in a sprint car crash at Southern Iowa Speedway in Oskaloosa, Iowa. The injury forced him to miss the final 15 races of the 2013 Cup season.
He missed three Cup rounds in 2014 after he struck and killed 20-year-old driver Kevin Ward Jr. in a sprint car race in Canandaigua, New York.
Last season, he competed in all the events but finished 28th in the standings with a career-worst average finish of 24.8.