Apprentice Jackson Murphy has been taken to hospital after falling shortly after the start in the fifth race at the Gold Coast.
Murphy was riding favourite Dream Master which jumped in front but appeared to duck in tossing Murphy to the turf.
Paramedics attended to Murphy, who was conscious, on the track before he was taken to hospital for observation.
Murphy's master Chris Anderson said the young rider was complaining of a sore leg but appeared to have escaped serious injury.
"He is being kept in hospital for observation and we are hoping he gets the all clear to go home on Saturday night," Anderson said.
Murphy returned recently after spending four months on the sidelines after breaking a wrist in a fall at Doomben in December.