Apprentice Tahlia Hope has undergone surgery on a fractured ankle that will keep her out of the saddle for at least 12 weeks.

She had surgery on Thursday night to insert three screws and a plate.

Her father, trainer Shannon Hope, expects she will be released from hospital on Saturday.

He said Tahlia was unseated at the Ballarat jump-outs on Thursday and ended up underneath a horse which then stood all over her.

"The best case scenario is she'll back race riding in 12 weeks," Hope said.

"The amount of calls we've had has been sensational and every second person says whatever you do is do the physio and the rehab and take the time."

Hope said the injury could not have come at a worse time as his daughter was preparing to head to Warrnambool next week to Daniel Bowman's stable in preparation for the winter carnival.

But he said Tahlia's injury needed to be put into perspective following the death of track rider Riharna Thomson in Canberra on Friday from injuries she received in a fall earlier in the week.

"There is often someone worse off," Hope said.

"Look at the poor girl who has died in Canberra.

"Tahlia will be back in 12 weeks, unfortunately she won't be."

Hope said the St John of God Ballarat Hospital had been "sensational" in their care of his daughter after the right surgeon was available to operate.