Jockey John Velazquez was undergoing surgery to have his spleen removed hours after he was thrown from his horse in a race at the Breeders' Cup.
Velazquez's agent Angel Cordero Jr. told a Santa Anita spokesman by phone that the jockey was about to be released from a Pasadena hospital after he was thrown from Secret Compass and hit the track hard during Saturday's first Breeders' Cup race when doctors discovered internal bleeding.
Cordero says Velazquez was immediately taken to surgery for the spleen removal.
The 41-year-old New York-based jockey has won most of the nation's major stakes, including 13 Breeders' Cup races.
The filly, Secret Compass, was euthanized on the track after breaking her leg during the $2 million Juvenile Fillies.