Tommy Berry has been stood down from his remaining rides at Randwick and sent for X-rays after being dislodged from Kasiano Lad in the fourth race on Saturday.
The top jockey came off Kasiano Lad in the final 100m when the horse collapsed from suspected leg and pelvic injuries.
The Jason Coyle-trained galloper was later euthanased.
Berry complained of a sore neck and Racing NSW medical professional Dr John Saxon ruled him unfit to continue riding.
Saxon said he had sent Berry for X-rays as a precaution.
“Especially given he’s got a big week next week,” Dr Saxon said.
“His neck on the left side was sore and painful to touch and it was worse with movement. It would have impaired his riding action.”
Berry scored an early win on Hawkes Racing two-year-old Star Turn and his injury cost him a stable double aboard promising three-year-old Secret Prophet.
Sam Clipperton picked up the winning mount.
Preliminary reports on Kasiano Lad indicate the horse might have suffered an injury to its near foreleg and possibly an injury behind to its pelvic region.