Glen Boss has all but conceded the Victoria Derby to Sydney colt Complacent.

Boss rides maiden galloper Bring Something in Saturday's Group One staying test for three-year-olds and rates his mount a top five chance.

But he is sure the Peter Snowden-trained Complacent, winner of the Spring Champion Stakes at Randwick, is the horse to beat.

"If I was riding Complacent tomorrow, I'd be very confident I just win the race," Boss said.

"I'd be sleeping pretty comfortably if I was Kerrin McEvoy tonight, thinking that I could win the Derby."

Complacent lost favouritism for the Derby (2500m) at Flemington when he drew barrier 16 on Wednesday but retains the faith of his stable and the respect of his rivals.

Spring Champion placegetter and last week's Group Two Vase winner Savvy Nature heads TAB's market at $4.80 while Polanski has been the big firmer from $8.50 to $5.50 equal second favourite with Complacent since drawing barrier one on Wednesday.

Boss took plenty of notice of Complacent's Spring Champion Stakes win and was suitably impressed.

"The trip looks like it will be the least of his worries and I reckon he'll love Flemington," Boss said.

"He's well found in the market but he should be because he just looks like the winner to me."

Boss, a Victoria Derby winner on Hit The Roof in 2000, has a good opinion of Bring Something but says the Derby might be coming too soon for the Ken Keys-trained gelding who the jockey described as "a work in progress".

Bring Something was fourth in the Bill Stutt Stakes and fifth in the Norman Robinson.

"I'm expecting my horse to run well and I think in the autumn when he furnishes you'll see a better horse," Boss said.

"I can't see him winning tomorrow. I hope he does, but I can't see it.

"I've got him in the top five, but outside the top three."

Complacent is the leading chance of Darley's three runners but Norman Robinson Stakes runner-up San Diego and Geelong Classic runner-up Tupac Amaru are also in contention.

"Complacent is a high-quality colt, a striking individual and we've had him pegged as the horse with the most ability of the three," Darley's Jason Walsh said.

"But they are all there deserving of their chance.

"We've got plenty of darts there with different racing styles and that gives us a good chance hopefully tomorrow."

Hugh Bowman is hoping for his third Victoria Derby win in four years when he rides Polanski, who he partnered to win the Norman Robinson Stakes last start.

"I was lucky to get on him but I might have just got on him at the right time," Bowman said.