The extent of any injury to valuable colt Zoustar will not be known for a couple of days.

Zoustar disappointed in Saturday's Canterbury Stakes won by Appearance, finishing eighth of the 10 runners and was later found to have mild lameness in a foreleg.

He has received anti-inflammatory treatment and his leg has been iced.

Trainer Chris Waller said because of that treatment the extent of his injury would not be known until at least Monday.

"He seems OK," Waller said.

"We've treated him so we won't really know until Monday."

Valued at $18 million after his win in the Group One Coolmore Stud Stakes in November, Zoustar carried the colours of Sheikh Fahad al Thani for the first time on Saturday.

The owner of 2011 Melbourne Cup winner Dunaden bought into the colt after shares became available in January, joining Widden and Woodside Studs in the ownership.

Had he won the Canterbury Stakes, Zoustar's previous owners would have reaped an extra $2 million.

His only other scheduled start during the Sydney autumn carnival is the $2.5 million TJ Smith Stakes on April 12.

A win in that race would cement a trip to Royal Ascot in a bid to enhance his prospects as a dual hemisphere sire.

Jockey Jim Cassidy thought he raced a little on the fresh side on Saturday, giving Waller another problem heading to the TJ Smith.

The trainer said he would have to assess the best path to the race which would more than likely be a barrier trial.

"It's a balance to make sure he's not too fresh and finding a trial that's not too close to the race," Waller said.

Newmarket Handicap winner Lankan Rupee now holds sway in TJ Smith betting at $4.60 with the TAB ahead of Canterbury Stakes runner-up Notlisten'tome at $6 with Zoustar, Buffering and Snitzerland all at $8.