Godolphin colt Astern is a market mover ahead of the declaration of the final field for the Golden Slipper.

Astern, who has always been the leading contender among Sheikh Mohammed's team, has firmed from $11 to $8 with the TAB with Extreme Choice the $2.80 favourite ahead of his Mick Price-trained stablemate Flying Artie at $6.

Former Slipper favourite Capitalist shares the fourth line of betting at $11 with Kiss And Make Up.

Extreme Choice and Flying Artie, who ran one-two in the Blue Diamond Stakes, will gallop on the course proper at Rosehill on Tuesday morning over the 1200 metres of the Slipper.

The final field for the $3.5 million Slipper will be known at 9am with the barrier draw later in the morning.

The Slipper has a maximum field size of 16 with one place opening up following the withdrawal on Monday of the Paul Messara-trained Weatherly.

Godolphin could have five runners but trainer John O'Shea said after Souchez's win in Saturday's Pago Pago Stakes, that colt was more likely to be kept for the ATC Sires' Produce Stakes over 1400 metres.

Calliope, Telperion and Tessera are the other Godolphin horses in contention.

Astern missed his scheduled Slipper lead-up, the Todman Stakes, with an elevated white cell count on race day and instead ran in a barrier trial last Thursday, winning comfortably.

The Gai Waterhouse-trained Kiss And Make Up caused an upset in the Todman when he beat odds-on favourite Capitalist who was determined to be slightly lame after the race.

Co-trainer Peter Snowden disagreed with the vet's assessment although the colt was later found to have some soreness in his back.

A decision on whether his stablemate Defcon, who staged a last-to-first sprint to win the Black Opal Stakes at Canberra, takes part in the Slipper will be made after the pair work at Randwick on Tuesday morning.