Chris Waller concedes Boban profiles as a risk on soft ground but the leading trainer insists one of the stars of last year's spring carnivals in Sydney and Melbourne must start in the Apollo Stakes at Randwick on Saturday.

Waller accepted with three horses in the weight-for-age race but he says he will scratch Sizzling to run the juvenile Group One winner in the $500,000 Futurity Stakes at Caulfield.

He has no such luxury with Boban as the four-year-old tries to lift on an unplaced return to racing behind Appearance in the Expressway Stakes.

Rain ensured Wednesday's Warwick Farm meeting went ahead on a heavy track and although Randwick escaped most of the deluge, Waller has a concerned eye on the forecast for the rest of the week.

"I'm hoping the track's not too bad," he said.

"I would be concerned on a slow track because he's got poor wet-track form.

"He needs to run and I need to find out what he is like on a wet track as a mature horse."

Boban, winner of the Epsom Handicap and the Emirates Stakes last year, has been made a $2.90 favourite to regain some of the autumn momentum he may have lost in the Expressway.

Appearance, with three wins from six starts in rain-affected going, is a clear second favourite at $3.70 for the Apollo.

Sizzling is Melbourne-bound after pleasing Waller since taking the minor placing in the Expressway.

"He's got the benefit of a run under his belt and he has been working very well left-handed and that gives me a bit of confidence to take him down there," Waller said.

Trainer Peter Snowden will also send Darley veteran Pinwheel south for the Futurity.

"I have thought about it all day and I've decided to give him his chance in the Group One," Snowden said.

Promising Not Listenin'tome is also an acceptor for support races at Randwick and Caulfield but co-trainer Michael Hawkes says no decision had been made on where the sprinter will start.

"Obviously the race in Melbourne is an easier race being a three-year-old race but in saying that the horse is in Sydney and we'll just see what happens," Hawkes said.

A barrier trial winner at Rosehill on Tuesday, Not Listenin'tome has been made the $2.80 favourite to beat older horses in the Southern Cross Stakes at Randwick.