Seabiscuit has been a hit at the US box office

Gary Stevens suffered a collapsed lung and fractured vertebra when he was thrown off his mount during a weekend race, doctors said.

He was described as being in a "fair and stable" condition at Northwest Community Hospital, Illinois.

Stevens, a professional jockey who has won the Kentucky Derby three times, plays George Woolf in Seabiscuit, a racing drama starring Tobey Maguire that reached the top five at the US box office.

It is the true story of an undersized horse that lifted the spirits of the US with its achievements during the Depression, and is tipped for possible Oscar recognition.

Stevens was hurt on Saturday during Illinois' prestigious Arlington Million race.

He was riding Storming Home when it veered to the right into the path of another horse.

Hospital officials said they were not sure when he would be released.