New York racing authorities on Monday barred trainer Bob Baffert from entering horses in next month's Belmont Stakes following the positive drug test against his Kentucky Derby winner Medina Spirit.
In a statement, the New York Racing Association (NYRA) said Baffert would also be suspended from all racing as well as occupying stall space at Belmont Park, Saratoga Race Course and Aqueduct Racetrack.
"In order to maintain a successful thoroughbred racing industry in New York, NYRA must protect the integrity of the sport for our fans, the betting public and racing participants," NYRA President Dave O'Rourke said.
"That responsibility demands the action taken today in the best interests of thoroughbred racing."
The suspension from the June 5 race was the latest blow to hit embattled Hall of Fame trainer Baffert, who has been at the eye of a doping controversy after his horse Medina Spirit tested positive for a banned steroid at the Kentucky Derby.
Baffert has been barred from racing horses at Churchill Downs in Kentucky following the drug test, but was allowed to enter Medina Spirit at last Saturday's Preakness Stakes, the second leg of US racing's Triple Crown.
Baffert could face a lengthy suspension from racing and see Medina Spirit stripped of its Kentucky Derby victory if a second analysis of the three-year-old's sample from the race returns a positive result.
Medina Spirit tested positive for traces of the banned steroid betamethasone after rompting to victory in the Derby on May 1.
Baffert initially vehemently denied administering the drug to the horse but later admitted it was contained in an ointment used on the horse to treat a skin complaint up until the eve of the Derby.
It is the latest controversy to embroil Baffert, whose horses have failed at least 29 drug tests during his career.
The NYRA statement said it had taken into account the fact that Baffert had failed doping tests in Kentucky, California, and Arkansas.
"NYRA expects to make a final determination regarding the length and terms of Mr. Baffert's suspension based on information revealed during the course of the ongoing investigation in Kentucky, such as the post-Kentucky Derby test results of Medina Spirit," the statement said.