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.

“He was going better than he was [in his workout] before the Santa Anita Derby,” Stevens said. “I was getting goosebumps down my neck. As we were rounding into the stretch, I was thinking how much I was going to let him gallop out.

“Thankfully, when (the bone broke), I had a hold of him,” he continued. “He looked out for me and I looked out for him. He pulled himself up.

“He was loving the racetrack,” Stevens added. “He was getting over it nice. I wanted to make sure that everyone knew that the track was perfect. It’s just one of those deals.”

Royal Mo, who captured the Robert Lewis and finished third in the Santa Anita Derby, had topped the also-eligible for the Kentucky Derby at Churchill Downs May 6. When Royal Mo failed to draw into the 20-horse field, Shirreffs immediately targeted the Pimlico’s Middle Jewel of the Triple Crown.

“It’s very difficult,” Shirreffs said. “Our hopes and dreams were with Royal Mo. Mr. and Mrs. Moss and my wife, Dottie, were excited to see him run. We’re all obviously devastated.”