Jockey Victor Espinoza fractured the C3 vertebrae in his neck July 22 after a fall during training at Del Mar.

According to Espinoza's agent, Brian Beach, the rider will stay overnight at Scripps Memorial Hospital La Jolla for observation. Beach said there have been no signs of paralysis and no other fractures but that Espinoza is experiencing numbness in his left shoulder and arm from a "stinger," an nerve injury often associated with football.

"He has regained about 50% of the feeling already," Beach said. "Doctors are optimistic he'll fully recover fairly quickly."

Beach said he was "not sure how long (Espinoza) will be out at this point."

Espinoza's injury occurred during a work aboard Kona Gold Stakes (G2) winner Bobby Abu Dhabi. Espinoza was unseated as the chestnut colt fell near the wire. Both horse and rider were motionless on the racetrack immediately after the fall.

Espinoza was on his side until paramedics arrived. Paramedics carefully rolled Espinoza onto his back, put a neck brace on him, and slid a backboard under the rider to take him off the dirt track and load him into an ambulance.

Bobby Abu Dhabi died from an apparent cardiac event, according to Brian Trump, the racing manager for Rockingham Ranch, which owned the Macho Uno colt in partnership with David Bernsen. Trump said the Peter Miller-trained Bobby Abu Dhabi was working for a start in the July 28 Bing Crosby Stakes (G1).

Espinoza, 46, was inducted into the National Museum of Racing's Hall of Fame in 2017. He rode American Pharoah to Triple Crown victory in 2015.