English visitor My Ambivalent will miss the Caulfield Cup with a hoof injury but is expected to be fit for the Melbourne Cup in three weeks.

Trainer Roger Varian's assistant David Eustace made the call to withdraw the mare from Saturday's $3 million race after inspecting her at the Werribee quarantine centre on Tuesday morning.

"She is just not quite spot-on and there is no use having a setback and trying to rush them into a Group One," Eustace said.

"We don't want to come out here and not give her her fair shot, so we had to draw stumps on Saturday and look towards three weeks time."

My Ambivalent had worked in great order at Werribee on Saturday morning but was lame a day later.

"She hasn't got an abscess or anything. It's something completely different, just bruising on her hoof," Eustace said.

He said he expects My Ambivalent to be shod on Wednesday morning after which she should be able to work.

"I'm sure she will be right tomorrow morning but missing three days, having done a piece of work, was just too long," he said.

It was a day of drama at the Werribee quarantine centre on Tuesday morning when Japanese galloper Raizan and Lord Van Percy both put a foot in a hole which had developed after an irrigation pipe on the outside of the track developed a leak and caused the ground to move.

Red Cadeaux's gallop was slightly interrupted when Japanese horses Admire Rakti and Admire Inzumana were still cantering off the track as he was finishing a strong gallop in the straight.

The final field and barrier draw for the Caulfield Cup will be decided on Tuesday afternoon.