A bout of the flu has forced Ballarat jockey Michelle Payne to relinquish the ride on English galloper Kaspersky in the group 1 Toorak Handicap at Caulfield on Saturday.
Luke Nolen will replace Payne in the saddle.
Payne has been laid low over the past week and missed two gallops on Kaspersky at Werribee – the latest on Wednesday – where the Jane Chapple-Hyam-trained horse has been undergoing quarantine since arriving in Melbourne from England less than two weeks ago.
She also missed riding Kaspersky at Newbury in England in August because of illness.
The 2015 Melbourne Cup winning jockey was looking forward to partnering Kaspersky after riding him at Royal Ascot in June.
"There's lots of flu going around Melbourne at the moment and I've got a bit of a head cold myself," Chapple-Hyam said.
"So, unfortunately, she's not able to ride and we've gone and engaged Luke Nolen.
"Mr and Mrs Clarke (owners Ernest and Ronda) are happy with that.
"I think if someone's ill and they admit they're not able to ride a horse then good on her for putting her hand up and saying she's not 100 per cent.
"That's all the Clarkes and I ask for and I think we've found a very good replacement."
Chapple-Hyam first met Nolen in 2012 when Black Caviar was housed at her Newmarket stable ahead of her win at Royal Ascot and said Kaspersky was in good hands.
"I at least know the face and know the name," she said.
Kaspersky is a $17 chance in final field markets for Saturday's 1600m-race and has drawn barrier three in the field of 18 plus one emergency.
Whether Kaspersky heads to the Cox Plate to take on Winx at Moonee Valley on October 28, or runs in the Kennedy Mile at Flemington the following week, will be determined by his performance on Saturday.
Chapple-Hyam said a decision whether Payne would get the chance to ride Kaspersky in his next outing was up to the owners.
"It's their horse and I'll leave that call with them," she said.
Payne claimed her first Group One win in the 2009 Toorak Handicap aboard the Bart Cummings--trained Allez Wonder.