A Caulfield Cup start for topweight Americain will depend on Melbourne's weather.

A warning has sounded from the camp of 2010 Melbourne Cup that a firm track at Caulfield would rule the horse out of the race.

And with hot, windy weather forecast for Saturday, the prospect of at least a good 2 rating is likely, particularly with the race programmed as the eighth on the 10-event card, by which time overnight watering will be of no effect.

Americain's handler Stephanie Nigge who has supervised the horse's past two Australian preparations said Americain routinely wears concussion plates to protect him from the shock of firm tracks.

But she said trainer Alain de Royer-Dupre would have no hesitation in ordering the horse to be withdrawn if the track was too firm.

"The boss says I should take him out of the race if it is firm," Nigge said.

Americain drew barrier 19 in the $2.5 million race for which he is a $19 chance.

Glencadam Gold holds favouritism for the Cup at $4.50 despite drawing second from the outside on the 18-horse field.

Americain's French compatriot Dunaden, who will run whatever the track condition, is second pick at $7.