A wet track could rule valuable colt Zoustar out of the $2.5 million TJ Smith Stakes.

Trainer Chris Waller said he would have no hesitation in pulling Zoustar out of the 1200-metre sprint on Saturday if the Randwick track was rated slow.

Waller said the decision would be made with the colt's owners who include Qatari's Sheikh Fahad Al Thani, owner of 2011 Melbourne Cup winner Dunaden.

"Jimmy (Cassidy) came and rode him this morning," Waller said.

"His work was good but not as good as it would be on a firmer track.

"He won't run on a wet track but we need to work out how wet.

"I wouldn't need much convincing not to run if it's not on the better side of slow.

"We can wait till the following week and the Royal Sovereign Stakes against his own age or the All Aged Stakes."

Sheikh Fahad is keen to take Zoustar to Royal Ascot in June to try to enhance his value as a dual hemisphere stallion.

Zoustar is an $11 chance in the TJ Smith and has drawn well in barrier six.

The forecast for Sydney leading up to Saturday is for showers.