Gun colt Merchant Navy is on target to make his return in the Rubiton Stakes at Caulfield as he builds to his main autumn target, the Newmarket Handicap.

Merchant Navy is one of the headline nominations for Saturday's Group Two Rubiton (1100m), one of two options considered for his return along with next week's Lightning Stakes.

"It looks like he'll be running on Saturday," trainer Aaron Purcell said.

"We're going to accept and then just work the field out but most likely Saturday is going to be his kick-off point."

Merchant Navy charged home to win the Group One Coolmore Stud Stakes (1200m) at Flemington at the end of his spring preparation.

And while his autumn campaign is being geared around having him at his peak second-up in the Group One Newmarket Handicap (1200m) next month, Purcell still expects Merchant Navy to be hard to beat in his return.

"The Newmarket is his target," he said.

"Obviously we want him to run well first-up. The rail is back to true on Saturday and it doesn't look like being a huge field. It looks like a race he should be pretty hard to beat in.

"He's not going there just for fun. He's there to win.

"Obviously he's a get-back horse and Caulfield sometimes can play on-speed so the way the races are on the day is going to make a difference.

"But the way he's going, if the track is fair, he probably should be winning."

Merchant Navy's only defeat in six starts was the Group One Golden Rose over 1400m in Sydney last spring.

Purcell said Merchant Navy was probably a little bigger and stronger than the spring while his work has been of a similar standard.

"He's quite an intelligent horse who doesn't do more than he has to," Purcell said.

"He wins every gallop he's in but he never wins by far.

"And he's the same now in his work as he was in the spring. We'd like to think he's going to be racing just as well if not better.

"We've trained him as a sprinter this whole preparation and kept him fresh and sharp. All his work and trials have been really good."