Chris Waller is poised to play a leading role on Sydney's biggest spring race day but the champion trainer also senses an opportunity in Saturday's feature in Melbourne.

Waller starts Hawkspur in the Group One Turnbull Stakes at Flemington and his optimism about the gelding's chances stems from his luckless performance in the same race last year.

Hawkspur finished a close fifth in the 2000m Group One race last spring after being blocked for a run at a crucial stage.

"One of the reasons we brought him down this year was that he could have won it (last year)," Waller said.

Hawkspur heads into this year's Turnbull off a Chelmsford Stakes win and a fourth in the George Main Stakes - the same results as last year only Waller says the gelding is a stronger horse this time around.

The difference this year is that Hawkspur is not being prepared for the 3200 metres of the Melbourne Cup.

"He's come back well. He's probably a bit stronger. It's the perfect race for him," Waller said.

While Hawkspur flies the flag for Waller's stable in the Turnbull, Sydney's premier trainer has strong representation in the three Group Ones at Randwick including three of the leading Epsom Handicap contenders.

Hawkspur is an $11 chance in the Turnbull with Lucia Valentina at $5.50 and last year's winner Happy Trails at $6.

The Caulfield Cup hopes of Sertorius plunged on Friday afternoon when he was scratched from the Turnbull due to an elevated white count.

The race looms as an important day in the spring campaign of Melbourne Cup favourite The Offer, with Gai Waterhouse convinced he is tracking perfectly towards his mission.

The Offer has been based at Flemington for a month but will race for the first time at the track where connections hope he will win the Melbourne Cup next month.

"He's got his foot on the till. He's ready to rock and roll," Waterhouse said.

"He's very fit. He's very happy and healthy. He'll just run a huge race."

The Offer ran on strongly for fifth in the Dato Tan Chin Nam Stakes at the first start of his campaign.

But Waterhouse believed Tommy Berry got too far back on The Offer in the Underwood Stakes when the gelding finished ninth, just over three lengths from the winner.

"He is aware that he's got to be closer," Waterhouse said.

Green Moon (2012), Makybe Diva (2005) and Let's Elope (1991) have completed the Turnbull Stakes-Melbourne Cup double in the past 30 years.