Royal Mo has fractured a bone in his hoof during a workout in preparation for next weekend's Preakness and was taken to a veterinary hospital for treatment.
Hall of Fame jockey Gary Stevens was aboard Royal Mo on Sunday when he says he heard a pop while turning into the stretch at Pimlico.
Trainer John Shirreffs says X-rays revealed a fractured sesamoid bone in the colt's right front hoof. Royal Mo's leg was placed in a boot and he was taken to the University of Pennsylvania's New Bolton Center. Sesamoid injuries can take 4 to 8 weeks to heal.
Shirreffs says there isn't any other damage to the Southern California-based colt.
Royal Mo didn't get into the 20-horse field for the Kentucky Derby, so Shirreffs had pointed him toward the Preakness, which is Saturday. The 3-year-old colt, owned by former A&M Records co-founder Jerry Moss and wife Ann, won the Robert Lewis Stakes and finished third in the Santa Anita Derby.