DEL MAR, Calif. -- Opening Day at the Del Mar Racetrack was marred Wednesday when a jockey was seriously injured after his horse fell and he was trampled by other horses, 10News reported.

It happened during the third race at Del Mar about 3 p.m. Wednesday, witnesses told 10News.

The horse, Mi Rey, was in the middle of the pack, along the rail, in the stretch and in front of a packed grandstand when it went down, appearing to break a front leg.

His jockey, Raphael Bejarano, fell to the track and was struck by at least one trailing horse, witnesses told 10News.

The motionless jockey was quickly put in an ambulance and transported to a nearby hospital. Officials at Scripps Memorial Hospital told 10News Bejarano is listed in fair condition and will be kept overnight for observation. A jockey told 10News an announcement was made in the jockey room that Bejarano suffered a broken collar bone and a fractured jaw.

Racing was alllowed to continue and Bejarano was replaced in a following race, track officials confirmed.

No one else was injured. Mi Rey was removed from the track in a horse ambulance. He was euthanized immediately, track officials said.

Late Wednesday, Del Mar officials released the following:

"X-ray examination at Scripps Hospital in La Jolla revealed that Rafael Bejarano, one of America’s leading jockeys, suffered multiple facial fractures as the result of a spill in the third race Wednesday, Opening Day of the 2009 Del Mar summer racing season.

According to Dr. Philip Sanderson, physician who initially examined Bejarano in the track first aid station, x-rays showed that Bejarano suffered fractures of the jaw, nose and orbital bones in the mid-stretch mishap which occurred when his mount, Mi Rey, broke down, unseating Bejarano, who appeared to have been clipped by a trailing horse.

Mi Rey suffered a catastrophic injury to his right front leg and was humanely euthanized.

Bejarano, top rider at Del Mar a year ago, also may have suffered an injury in the area of his left shoulder. Further x-rays were scheduled.

According to Sanderson, the 27-year-old native of Peru has been admitted to the hospital and will remain overnight. He also said there is a possibility he will have to undergo surgery to repair his facial injuries."