Top galloper Maldivian is believed to have suffered a suspensory ligament injury and could be out of the autumn.
The Mark Kavanagh-trained gelding wasn't among the nine runners for Saturday's Group 2 St George Stakes and was favourite for the Australian Cup but the injury could rule him out for the rest of the season.
In fairness to connections, Kavanagh is yet to confirm the injury until speaking to West Australian owner Joe Ricciardo but fixed odds operators have removed the classy galloper from Australian Cup markets.
Maldivian worked his way back into form in the spring to win the Cox Plate then resumed with a brave win in the C.F. Orr Stakes.
He would have been favourite for this Saturday's Group 2 St George Stakes (1800m) at Caulfield as his final lead-up to next Month's Group 1 Australian Cup.
Sydney galloper Theseo, third in the Orr, is likely to start favourite in the St George and has been elevated to favourite for the Australian Cup at $4.50 over last year's winner Sirmione at $6.50.
worked his way back into form in the spring to win the Cox Plate then resumed with a brave win in the C.F. Orr Stakes.