United States Hall of Fame jockey Javier Castellano has tested positive for the coronavirus and is self-isolating.

Castellano tested positive as part of a physical that officials at Gulfstream Park mandated as a prerequisite before being cleared to ride in Saturday's Florida Derby.

"After being in New York with my family last week, I was asked by Gulfstream to come early to Florida to get tested for the virus," he said on Twitter.

"I was asymptomatic all along. Unfortunately the test came back last night as positive. I am otherwise healthy but will follow the doctors orders to quarantine for the next 2 weeks. I have had no known contact with anyone that has tested positive.

"I appreciate the support from everyone including Gulfstream Park. Stay safe everyone and we will all get through this God willing."

Castellano last rode on March 15, when he had two mounts at Gulfstream. He returned to New York to see family afterward and was scheduled to ride at Gulfstream this weekend.

Gulfstream has issued tight restrictions for anyone entering the track, including jockeys.

Racing is continuing at the track in Hallandale Beach, Florida without anyone but essential personnel present.

Other states have stopped racing altogether and the famous Kentucky Derby has been moved from May to September.