Samantha Clenton will have surgery on a broken collarbone suffered in a multiple-horse fall at Taree while Jackson Murphy remains in hospital after damaging his spleen.
Four apprentices were taken to hospital after the fall on Monday.
Clenton spent the night in Port Macquarie Hospital while Murphy was taken to Newcastle.
Racing NSW safety officer Maurice Logue said Murphy was expected to stay in hospital for the next four or five days.
“Jackson has split his spleen but the bleeding has stopped,” Logue told Sky Sports Radio.
“Samantha is likely to have surgery as early as tomorrow. She also has bruising to her back.”
Kaylee Kirkwood was discharged from on Monday night after having stitches in a leg wound. She was cleared of any fractures.
Nyssa Burrells also appears to have escaped without any broken bones.
Earlier this month, Clenton celebrated her biggest win aboard Clearly Innocent in the Listed Luskin Star Stakes at the Scone carnival.
Monday’s accident happened when Clenton’s mount Bazza’s Boy fractured his leg with the other horses unable to avoid him.
Bazza’s Boy was unable to be saved.