Brilliant colt Exosphere is the odds-on favourite to win the Coolmore Stud Stakes but his trainer John O'Shea is taking a cautious approach.

Exosphere has been dominant in his three starts this spring in Sydney including the Group One Golden Rose and is at $1.40 with his stablemate Mogador and Blue Sapphire Stakes winner Keen Array at $8.50 in early markets.

"I think it's going to be a very competitive race," O'Shea said.

"There's genuine speed and last year if you drew inside (barrier) six, well you might as well have stayed at home because of the northerly blowing up the straight and you needed to draw the outside.

"If we got a scenario like that perpetuating on Saturday, well it wouldn't matter what price he was or how good he was, he's going to be vulnerable.

"So we're just hoping for a nice even run and I think whenever he gets in that scenario he's always competitive.

"We're happy with him."

Exosphere, who weighs in at around 600kg, had a look at the Flemington straight track in a jump-out last Friday.

"Nothing worries him. He's really happy," O'Shea said.

"He had a bit of a squeal this morning (Tuesday) which is about as excited as he gets.

"His condition is good and he's sound and fit and well."

Exosphere has won five of his seven starts. He ran last on debut as the $1.65 favourite and last at his other unplaced run as a $4.60 chance in the Golden Slipper after which he was found to have cardiac arrhythmia.

Mogador finished second to Keen Array in the Blue Sapphire at Caulfield last start and O'Shea said he would not be surprised if he was effective in the Coolmore.

Weekend Hussler (2007), Northern Meteor (2008) and Sepoy (2011) have won the race as odds-on favourites in the past decade.

Chris Waller has trained the past two Coolmore Stud Stakes winners - Brazen Beau (2014) and Zoustar (2013) and has Counterattack ($15) and Japonisme ($17) lining up this year.