Hugh Bowman has failed a concussion test, ruling the leading jockey out of the Coolmore Classic meeting at Rosehill on Saturday.
Bowman visited a neurosurgeon on Wednesday morning and was told he would not be able to return to riding until next week.
The regular rider of champion racemare Winx, Bowman fell heavily from Golden Slipper contender Performer in a lead-up race at Randwick on Saturday.
Bowman said he had been ordered to rest but is hopeful he can ride trackwork on Tuesday.
"I've still got a headache coming and going. I was very lucky really," Bowman said on Tuesday.
"If the doctors suggest I should wait I won't hesitate.
"I won't be taking any risks."
Bowman spent Saturday night in hospital with concussion and minor abrasions after the frightening fall.
He came off when her Chris Waller-trained stablemate appeared to take a step left in the straight in the Todman Stakes.
Waller said the incident made Performer's chances to get to the Golden Slipper harder but the main thing was Bowman was OK.
"Performer has to trial and he will do so and we will consider putting blinkers on," Waller said.
"It's not ideal but hopefully he will get there.
"More importantly it puts into perspective what they (jockeys) do as a job every day and the risks they take."
Winx is due to have her next start on Saturday week in the Group One George Ryder Stakes at the Golden Slipper meeting.
Bowman has ridden Winx to 22 of her 23 consecutive victories, including during the Chipping Norton Stakes two weeks ago when she broke Black Caviar's Australian Group One wins record with her 16th victory.