A Tuesday morning track gallop at Warwick Farm will determine whether Grandslam joins stablemate Explosive Jack in the Group 1 Australian Derby at Randwick on Saturday.
A winner of the Group 2 Alister Clark Stakes (2040m) at The Valley on March 13, Grandslam was taken to Sydney for the traditional Derby lead-up, the Group 1 Rosehill Guineas (2000m) on March 27.
After leading into the straight, Grandslam faded to finish 10th behind Mo'unga, beaten just shy of 11 lengths.
David Eustace, who trains in partnership with Ciaron Maher, said the horse over did it in front that day.
“He'll work on Tuesday and we'll make a decision after that,” Eustace said.
“He did a bit too much last time, so we need to see him in his work.”
Eustace said the stable was happy with the progress Explosive Jack was making heading to Saturday's Derby, adding the son of Jakkalberry would relish the trip.
Victorious in the Tasmanian Derby in February, Explosive Jack followed that with a third-place finish behind his stablemate in the Alister Clark Stakes before running second over 2200m in the Bendigo St Leger Trial on March 27.
“He galloped at Werribee on Saturday morning and worked well,” Eustace said.
“John Allen rode him and said it was his best piece of work in the prep and he's a horse that continues to improve.
“He was very unlucky at Bendigo. I thought he was the best horse in the race, he just got into a bad spot, no-one's fault, after being slowly away.
“He'll love the trip and any rain will help, although he's showing us that he's effective on top of the ground, but I think he's better with a bit of cut.”
The field with barrier draw will be finalised on Tuesday.