Sons Of John will start a run towards the Epsom Handicap when he resumes for emerging trainer Jason Attard in the Theo Marks Stakes.

Under Attard's care since a stable transfer last year, Sons Of John has won four races, the most notable being the Hawkesbury Gold Cup in June.

Now Attard has set his sights on the biggest mile race of the Sydney spring carnival, nominating Sons Of John for the $1 million Epsom at Randwick next month.

"We'll know a bit more after tomorrow," the 28-year-old said.

"But he's a great horse and his last 600 metres in the Hawkesbury Cup was just outstanding so we thought, why not have a crack at the Epsom if we can?"

Bookmakers are ignoring Sons Of John's Theo Marks claims at Rosehill on Saturday and Attard admitted the gelding needs further than 1300m.

"We'll be expecting him to do well but a midfield finish would be great."

Saturday's race represents another career milestone for the Attard as he moves up in the horse training world.

It will be the Hawkesbury trainer's first runner in a Group Two race.

Originally a worker at the local Reibycroft Stud, Attard took out his training licence five years ago and hasn't looked back, preparing his horses while also managing the farm.

Attard said setting up a metropolitan stable was still some way off.

"For the time being I'm very happy here in Hawkesbury, but I should be aiming towards it," he said.