Stock car driver AJ Allmendinger has been temporarily suspended after failing a drug test, NASCAR officials said on Saturday.
Steve O'Donnell, NASCAR's senior vice president of racing operations, made the announcement just hours before the start of the Coke Zero 400 at Daytona International Speedway but gave no details about what banned substance was found in Allmendinger's positive test.
Allmendinger was pulled from his Penske racing Dodge Charger and replaced by Sam Hornish Jr for the race.
"NASCAR notified Penske Racing this afternoon that A.J. Allmendinger was administered a drug test earlier this week and those results tested positive," Penske said in a statement.
"NASCAR has a strict drug testing program that Penske Racing fully supports.
"Penske Racing will work with NASCAR through this process and its next steps."
Under NASCAR's substance abuse policy, Allmendinger has 72 hours to request that his "B" sample be tested.
After a successful career in IndyCar racing, Allmendinger made the jump to NASCAR six years ago and has made 169 career starts but has yet to put his car on Victory Lane.
