Jerry and Ann Moss’ Royal Mo was transported to the University of Pennsylvania School of Veterinary Medicine’s New Bolton Center Sunday morning after sustaining a fracture of the sesamoid bone on the inside of his right forelimb at Pimlico Race Course, in Baltimore, Maryland.

A candidate for Saturday’s 142nd Preakness Stakes (G1), jockey Gary Stevens pulled up the 3-year-old son of Uncle Mo at the top of the stretch during a scheduled five-furlong workout. Veterinarians stabilized his injured leg with a splint before he was vanned back to the Preakness Stakes Barn, where radiographs revealed the injury.

“There isn’t any other damage, so that’s a very good thing for him,” said trainer John Shirreffs.

Stevens, who had taken a red-eye flight from Southern California Sunday morning to ride Royal Mo in his scheduled final serious preparation for the Preakness, said he heard a “pop” turning into the stretch while racing outside a workmate