Dwayne Dunn has been confirmed as the Cox Plate rider for Happy Trails after Damien Oliver's dramatic call-up to ride Fiorente.

Nash Rawiller was sacked as Fiorente's jockey after the Gai Waterhouse-trained horse finished fourth in Saturday's Turnbull Stakes won by Happy Trails with Dunn filling in on the winner for the suspended Oliver.

Happy Trails' trainer Paul Beshara said he was more than happy to have Dunn aboard.

"It was never completely locked in that Damien would ride and I'm happy that Dwayne will ride him in the Cox Plate," Beshara said.

"The horse has pulled up really well and will spend the next few days on the water walker."

Oliver's booking on Fiorente is for the Cox Plate and the Melbourne Cup in which the imported horse ran second at his first Australian start in 2012. He is now favourite for this year's Cup.

"I'm very excited to be on him," Oliver told racingvictoria.net.au.

"He's been running super so far this spring and he looks a great chance in both the Cox Plate and the Melbourne Cup."

Fiorente is on the third line of betting for the Cox Plate with Atlantic Jewel favourite over It's A Dundeel who beat her in the Underwood Stakes.

A foot abscess is threatening It's A Dundeeel's scheduled start in the Caulfield Stakes with the four-year-old to be monitored over the next few days.

Rawiller gave up rides at Sydney's two richest spring meetings to ride Fiorente in Melbourne, missing last month's $1 million Golden Rose and Saturday's Epsom/Metropolitan meeting at Randwick.

In an ironic twist, Rawiller is expected to ride Fiorente's stablemate Divine Calling in Saturday's Caulfield Guineas, replacing Oliver who will partner the Tony Vasil-trained Prince Harada.

Oliver has ridden Divine Calling to two wins in Melbourne in the lead-up to the Group One Guineas.