Montezuma Express, ridden by Saez, clipped the heels of the horse in front of him, knocking the jockey to the track, where he was apparently struck by trailing horses.
Saez, a native of Panama, was airlifted to Methodist Hospital in Indianapolis, where he was pronounced dead late Tuesday night, the coroner's office said.
"Juan Saez possessed an immense gift for riding horses and there is no telling how bright his future as a jockey would have been," the National Thoroughbred Racing Association President Alex Waldrop said in a statement.
(Reporting by Steve Ginsburg; Editing by Susan Heavey)
