Trainer Chris Waller is playing a waiting game with in-form stayer Patrick Erin.

First emergency for last week's Caulfield Cup, Patrick Erin needs a win to gain a Melbourne Cup berth.

The last-start Group One Metropolitan winner is an acceptor for Moonee Valley as well as figuring in entries for next Wednesday's Bendigo meeting.

Waller said Patrick Erin was a two-mile horse in waiting that had hit form in winning The Metropolitan at his last start.

But the trainer is now weighing up whether to start the stayer from a wide draw in Saturday's Moonee Valley Gold Cup or save him for the Bendigo Cup.

"Unfortunately he hasn't drawn very well and he does need to win a race to get his rating up even higher to get a start in the Melbourne Cup," Waller said.

"We opted not to run in the St Leger because of the wet track and the fact that it is not a Group race yet he couldn't get a re-handicap.

"It is either here from the wide draw or wait until the Bendigo Cup on Wednesday but a decision will be made closer to Saturday."

Joining Patrick Erin in Saturday's 2500m Group Two race are last year's quinella pairing of Who Shot Thebarman and Libran along with Egg Tart.

Waller said Who Shot Thebarman would appreciate firmer footing on Saturday.

"It is a stronger race than what he won last year but nonetheless it is a good yard stick as to where he might be heading beyond Saturday," Waller said.

"Libran has been very good this preparation.

"He has been plagued by bad draws but he finally has a good gate on Saturday and I am sure Hugh Bowman will utilise it to see him settle a lot closer."

Waller said he contemplated dropping Egg Tart back to 1600m.

"I am still a bit mindful that she hasn't attacked the line which is not ideal for a horse stepping up to 2500 metres," he said.

"She is well, her work has been good and from the good draw she should get a soft run but there is still a question mark over her staying ability."