Darley's Melbourne foreman Paul Snowden might have wished he could change Earthquake's Blue Diamond barrier but he insists he would not swap the horse for any other in the $1 million race.

Snowden, stable foreman for his father Peter, had the job of drawing Earthquake's marble at Tuesday's Blue Diamond draw.

While Snowden laments his choice of gate 15, a barrier that has resulted in the filly losing favouritism, he remains convinced she can win.

"I could feel Dad's hands going around my throat," Paul Snowden said of the moment he drew the wide gate.

Earthquake was joined by unbeaten colt Rubick, who drew gate 10, as $3 TAB favourite for Saturday's Group One but Earthquake then drifted to $3.30.

"You always cringe when you see double figures," Snowden said.

"When I got a chance to see where they were all drawn there's potentially six or seven horses drawn inside her who could go forward and if that's the case it strings them out a bit.

"You're banking on luck, but she can begin well and take up a spot so that puts her in front of most."

Darley has had a number of Blue Diamond runners in recent years including champion colt Sepoy who won easily in 2011 and Guelph who finished midfield as one of the favourites after jumping awkwardly last year.

Asked how Earthquake stacked up to previous years, Paul Snowden said: "She is as good a chance as we've ever had in the race, there's no doubt about that.

"Ability-wise I don't know. I'm not sure we've seen her at her best yet.

"I still think that's to come."

He said while the filly works strongly in her training gallops, she was a real racehorse.

"I thought she would win the Prelude but I didn't think she would win it like she did," he said.

"That just proves to you that she's a little racehorse and she goes to another level on the day."

Gerald Ryan's travelling foreman Sterling Alexiou described Rubick's draw as ideal.

"We were hoping for between seven and 12," he said.

"It's an ideal gate for the horse."

The Mark Kavanagh-trained Chivalry, who caught the eye with a closing third from last in the Prelude won by Rubick, is on the third line of betting at $8 and has barrier five.

Nayeli is on the fourth line at $9.50 as Gai Waterhouse chases her first win in the race.