Cahill is due to fly out with the Socceroos for Honduras on Sunday ahead of the first leg of their World Cup qualification play-off.

But in an unexpected move, Melbourne City coach Warren Joyce gave the veteran attacker his first start of the season in the top of the table clash against Sydney FC at AAMI Park.

A dejected Cahill left the pitch on 22 minutes after a clumsy challenge on Jordy Buijs. Reserve goalkeeper Dean Bouzanis told Fox Sports Cahill felt he had "tweaked" his ankle.

The 37-year-old appeared to be moving freely in the dressing room under the watchful eye of staff, but may well be a long shot for an arduous 30-hour plus trip to Honduras.

Later reports said the Aussie star's ankle had swollen, a sign of potential ligament damage. He was taken to hospital that night for scans.

The Socceroos take on Honduras away on November 11, before the home match on November 15.