Observer will be at Moonee Valley on Saturday, but will it be in the Vase or Cox Plate. 

Ciaron Maher's Observer, the unlucky runner from the Caulfield Guineas, will be a starter in a 2040m race at Moonee Valley on Saturday. 

But in which race the stable is still deciding. 

The Group 2 Drummond Golf Vase is the most likely lead-up to the Group 1 Victoria Derby (2500m) at Flemington on Saturday week, although there have been some discussions about the three-year-old contesting the Group 1 Cox Plate instead. 

A late entry fee of $200,000 will need to be paid for Observer to run in Saturday's Cox Plate as he was not among the latest round of acceptances taken on October 7. 

The final field and barriers for the Cox Plate will be announced on Tuesday morning. 

Ciaron Maher Racing's National Assistant Trainer Jack Turnbull said a brief discussion about a Cox Plate start had been aired on Saturday morning with a final decision to be made by Godolphin's Andy Makiv, Jason Walsh and Maher. 

"No decision has been made at this point," Turnbull said. 

"We are more than likely Vase, but whether that changes that is up to Andy, Jason and Ciaron, but either way the horse gets prepped the same way. 

"He could potentially go to The Valley on Tuesday morning, otherwise he will have a gallop at Cranbourne on Monday. 

"A trip away to The Valley, given it is there, he's a colt and still does a few things wrong, it's a genuine possibility." 

Observer was an unlucky third behind Autumn Boy in the Caulfield Guineas (1600m) on October 11 when held up for a run early in the straight. 

"We had to stop our momentum and come around," Turnbull said. 

"I thought he did really well to pick up and finish off as well as he did. A few people thought he could have done it better, but it's really hard when you are doing things wrong to do that. 

"The Group 1 placing was great, but there's still plenty left there."