A gallop by Americain at Caulfield on Saturday morning will decide whether he starts in Saturday week's Caulfield Cup.
If he gets the all-clear, he will be one of at least four international runners, alongside Dunaden, Quest For Peace and Jakkalberry.
Trying to join them will be John Gosden-trained Gatewood and Alain de Royer Dupre's Shahwardi, who would have to win the ballot-exempt 2400m Herbert Power Stakes at Caulfield on Saturday.
Ibicenco, trained by Luca Cumani, also may run in the Herbert Power.
Godolphin has selected Lost In The Moment and Cavalryman as its spring carnival representatives and the horses have gone into quarantine.
Ebor Handicap winner Willing Foe was being considered but failed on a wet track at Ascot yesterday.
Lost In The Moment finished a creditable sixth in last year's Melbourne Cup and has had four starts since for three placings and a fourth.
At his last start, he finished third in the 3200m Rose Bowl at Newmarket, with Cavalryman second.
Both are $51 with the TAB to win the Melbourne Cup.
Flemington trainer Danny O'Brien will use two gallops this week to decide if French import Prairie Star starts in the Caulfield Cup.
O'Brien told the Herald Sun it was an "an outside hope" Prairie Star would run in the Caulfield Cup, but he would be swayed by his work at Werribee today and at Caulfield on Saturday.
"If I was extremely pleased with his work, it would be a chance, but more likely he would make his Australian debut in either the Geelong Cup or the Coongy Handicap," O'Brien said.
He took over training Prairie Star more than a month ago, just before he went into quarantine at Newmarket, England. "He's really thrived. I saw him work at Deauville and then my stable foreman Paul Koumis looked after him at Newmarket."
Prairie Star worked with Mick Kent's Tac De Boistron at Werribee last Saturday. Kent is looking at running Tac De Boistron in the Geelong Cup and planning to work him there next week.