Cox Plate ambitions for Star Rolling will become clearer when a fitter specimen of the PB Lawrence Stakes winner takes aim in the Dato Tan Chin Nam Stakes.

The five-year-old mixed it with the weight-for-age horses in the autumn and after a gritty first-up Lawrence Stakes victory, trainer Peter Morgan is convinced the gelding is going even better this time.

Morgan is prepared to wait before locking in a major spring target, but admitted the Cox Plate was tempting.

The winner of Saturday's race earns automatic entry into the Cox Plate.

"If he won then I think you'd have to be saying we'd be heading that way," Morgan said.

"The next two runs, that's our plan at this stage and then we'll see what happens after that. All being well we hope we can be in the Cox Plate."

Star Rolling's autumn included a close third to Fiorente in the Peter Young Stakes and an unplaced Australian Cup run.

But Morgan wasn't as happy with the gelding then and jockey Stephen Baster has also become a fan since jumping aboard this campaign.

"If you look back at last preparation he only got beaten less than half a length by Fiorente and there's no better form around," Baster said.

"If he can improve any this preparation, hopefully he can be one of the top-line horses for the spring."

Star Rolling holds favouritism at $4 for Saturday's race but tough front-runner The Cleaner has been the notable mover in TAB betting, firming from $7 to $4.60.

The Tasmanian galloper's presence sets up an intriguing contest as he rolls along and makes his rivals chase.

Foreteller is after his third Group One weight-for-age win and his only Moonee Valley start was his Cox Plate fourth last spring.

Melbourne Cup favourite The Offer resumes and the past two Cup winners, Fiorente and Green Moon, have come through the race.

Nine subsequent Cox Plate winners have run in the race in the past 30 years with six winning both races.