European galloper My Ambivalent is in a battle to make Saturday's Caulfield Cup after suffering a stone bruise to her off-fore hoof.

An $18 chance in Caulfield Cup betting, My Ambivalent worked impressively under Hugh Bowman at Werribee on Saturday morning at the conclusion of her quarantine after arriving in Australia on September 27.

Bowman was glowing in his reports about the mare, however My Ambivalent was found to be lame the following morning.

The Roger Varian-trained My Ambivalent is now in a race against time to be fit for the race.

Racing Victoria stewards will continue to monitor My Ambivalent before final declarations and the barrier draw for the Cup on Tuesday.

Varian's assistant David Eustace said a Caulfield Cup start would depend on whether My Ambivalent could gallop on Tuesday otherwise she could go straight to the Melbourne Cup.

Lucia Valentina, who also had an injury scare before her impressive victory in the Turnbull Stakes at Flemington on October 4, retains favouritism at $5 for the Caulfield Cup ahead of Japanese raider Bande at $8.50.

However the best backed runner in the race has been last year's runner-up Dandino, to be ridden by Craig Williams, who has firmed from as much at $35 to the third line of betting at $9.50.

One horse that won't be taking his place in the race is last year's Bendigo Cup winner Sertorius.

The Jamie Edwards and Bruce Elkington-trained galloper missed a start in the Turnbull Stakes because of a high white cell count but turned in a solid effort when ninth behind Fawkner in Saturday's Caulfield Stakes over 2000m.

Edwards has elected to keep Sertorius for the Geelong Cup over 2400m on October 22 in the lead-up to the Melbourne Cup (3200m) on November 4.