The Blue Diamond Stakes field will be finalised on Tuesday but Lindsay Park still does not know whether a filly who was one-time favourite will be among the final acceptors.

Bold Bastille's Blue Diamond fate will be determined via a Tuesday morning track gallop, just a few hours before final acceptances are taken for this Saturday's $2 million Group 1 at Caulfield.

Bold Bastille started a $2.10 favourite in the Group 2 Blue Diamond Prelude (1100m) at Caulfield on February 10 and showed early speed to lead but weakened in the straight to finish sixth, almost three lengths from winner Hayasugi.

A veterinary examination revealed the filly to be lame in the off foreleg.

Ben Hayes, who trains the daughter of Brazen Beau in partnership with his brothers Will and JD, has been happy with Bold Bastille since but will give her a searching workout at Euroa on acceptances morning to see if she is fit to take her place.

"We're going to gallop her Tuesday and that's when we'll make our decision if we're going to run in the Diamond," Hayes said.

"We've got the option to wait and run her down the straight the week after.

"So we've just got to see how she gallops, talk to the owners and then we'll make a decision."

The Listed Furphy Trophy (1000m) at Flemington on March 2 looms as the back-up option if she doesn't run in the Diamond, for which she has blown out to $34.

The $270,000 Inglis Premier Yearling Sale purchase was the initial favourite for the Blue Diamond after a brilliant win in the Inglis Banner (1000m) at The Valley on Cox Plate Day.

Bold Bastille is one of two potential Blue Diamond starters for the Hayes family, who won last year's edition at Sandown with Little Brose, with Zestiman in line to run.

The Dream Thoroughbreds-owned son of Zoustar won at Flemington at his January 13 debut before finishing fifth, beaten 1-3/4 lengths, in the $2 million Inglis Millennium won by Fully Lit on February 10.