Sydney Cup weights and jockey bookings will be left in abeyance until a final decision is made on a start for the Lloyd Williams-owned stayer Efficient.
Veteran stayer Efficient holds the key to crucial riding engagements in Saturday's Sydney Cup.
If the Lloyd Williams-owned gelding is not among the acceptances on Thursday, weights for the 3200m Group One feature will be raised 2.5kg.
If he is declared for the final field the handicaps are increased 1.5kg and he will carry 58kg topweight.
Favourite Permit will go up from 52kg to 53.5kg if Efficient runs and will be ridden by Kerrin McEvoy but if he gets an extra 1kg Hugh Bowman will be aboard.
The acceptance of Efficient does not guarantee he will run with stewards to send vets to inspect him on Friday if he comes to Sydney from Melbourne.
Williams was upset when Efficient was scratched from the Chairman's Quality last Saturday week after vets determined he was lame on the off foreleg after a raceday inspection.
Racing NSW chief steward Ray Murrihy said the 2007 Melbourne Cup winner would be given every opportunity to prove his fitness.
"We will wait for the horse to accept and then we will ask the vets to inspect him on Friday," Murrihy said.
"Two vets agreed he had grade one to two lameness last time which is not too serious.
"I understand he has gait peculiarities and he will be given every opportunity to prove his fitness. He will be able to warm up and not just be pulled out of the raceday stalls."
Efficient has been sparingly raced since his Melbourne Cup triumph with the 2009 Group One Turnbull Stakes his sole win from 14 starts.
Permit's trainer Chris Waller will also have Hawk Island and last year's winner Stand To Gain in the Cup.
The out-of-form Stand To Gain has been given an unorthodox preparation with Waller sending him south to Robert Smerdon for some jumping practice.
He will contest a 2400m hurdle trial at Cranbourne on Tuesday, return to Sydney for the Cup, then be sent back to Melbourne where his future lies over the jumps.
Permit won the Chairman's Quality when ridden by Corey Brown who copped two careless riding suspensions in two days, ruling him out of the Sydney Cup meeting.
If Efficient is not in the field, Drunken Sailor becomes topweight with Damien Oliver to ride.
