Mrs Onassis is still in the mix for the Oakleigh Plate with a final decision to be made after she gallops on Tuesday morning.
Trainer Gerald Ryan said his original thought had been to wait another week or two but he had been persuaded by the mare's owner Gerry Harvey to delay the Oakleigh Plate decision.
"Gerry asked me not to make up my mind until tomorrow," Ryan said.
"If she works well we'll go ahead and run.
"She's fit enough to run on Saturday and if it was a Benchmark 95 I wouldn't hesitate.
"Last week with the heavy track she just couldn't do as much as I would have liked going into a Group One race first-up.
"I'll make the decision in the morning."
If Mrs Onassis does head south to Melbourne for the Oakleigh Plate at Caulfield she will be ridden by Chris Symons.
Mrs Onassis won two stakes races during her last campaign including the Listed Alinghi Stakes at Caulfield over the 1100 metres of the Oakleigh Plate.
She showed her readiness for a return on February 5 when she beat Oakleigh Plate entrant Ortensia decisively in a Rosehill barrier trial.
After Mrs Onassis gallops in the morning, her stablemate Charlie Boy will step out in a barrier trial at Rosehill.
The winner of his debut in November, Charlie Boy has come in for support with bookmakers to win the $3.5 million Golden Slipper.
TAB has him at $17 on the fifth line of betting with Saturday's Widden Stakes winner Overreach heading the market.
"I'm very pleased with him and the plan is to go to the Silver Slipper," Ryan said.
The winner of the Group Two Silver Slipper (1100m) on March 2 gains automatic entry to the Gold Slipper five weeks later.