Kentucky Derby champion Medina Spirit who offered coach Bob Buffert a record seventh victory in the race, failed the drug test.
Buffett said he was “shocked” after the horse was tested above the limit for betamethasone and insisted that he had never used the substance.
He said, “I took the most hits in the race for something I didn’t do.”
The soul of the city, on which John Velasquez rides, Won America’s most famous race At Churchill Downs on May 1.
Buffett, 68, was the first coach to win the US Triple Crown for 37 years when the American Pharaoh completed the Kentucky Derby, Breakness Stakes and Belmont Stakes trilogy in 2015.
The Hall of Fame coach repeated his hat-trick with Justify three years later.
But on Sunday, he told reporters that Medina Spirit had tested positive for 21 pg of the anti-inflammatory drug betamethasone, above the Kentucky Racing threshold of 10 pg per milliliter.
“This is unfair to the horse,” said the California-based trainer. “I’m not embarrassed, I feel like I’ve been robbed.”
“But I will fight it with its teeth and nails, because I owe it to the horse; I owe it to the owner and I owe our industry.
“There are problems with racing, but not Bob Buffett. I don’t believe in conspiracy theories, but why is this happening to me?”
Buffett said Spirit City has not been formally excluded from the Kentucky Derby, although this could still happen after the completion of testing and other processes.
“That should have happened,” said Buffert. “There is a problem somewhere. It didn’t come from us.”
Churchill Downs banned Buffett from participating in racing.
“If the results are upheld, the Medina Spirit results in the Kentucky Derby will be invalidated and Mandelon will be declared the winner,” she said in a statement.
“Failure to comply with the rules and medication protocols threatens the safety of the horses and riders, the safety of our sport, the reputation of the Kentucky Derby and all participants. Churchill Downs will not tolerate that.”
The coach had pledged last year to “perform better” after a number of positive tests appeared on his horses.
Last month he succeeded in rescinding a 15-day ban and disqualifying two of his horses – Gamine and Charlatan – after they returned samples containing the illicit raceday drug lidocaine, which has been attributed to cross-contamination from a pain relief patch worn by an assistant trainer.
Instead, Buffett received a $ 10,000 fine.