Godolphin's retained jockeys woes continued in Australia with William Buick to be flown into Sydney for Golden Slipper day as cover for an injured James Doyle.

The global operation was taking no risks as Doyle, who replaced James McDonald in December, struggles with injuries from a fall last month. He is no guarantee to be fit during the Sydney Carnival.

Doyle hasn't ridden since he fell from Pearls in the Triscay Stakes on February 13 and will visit a surgeon when he returns to Sydney this week. It is not the wrist he injured in the fall which is the concern rather a knee problem that has flared up after the tumble.

"It isn't clear when James Doyle will be back, so we have the advantage of having William retained at Godolphin as well and have called on him. He is a world-class jockey and as we have seen these riders can adjust very quickly when they fly in for these meetings," Godolphin trainer John O'Shea said.

"We saw it with James [Doyle] that these jockeys are the best in the world for a reason."

Doyle had replaced James McDonald, who was sacked after being disqualified for 18-months on a betting charge. In three months he had ridden 16 winners, including a winning treble at Randwick in January, and had a winning strike-rate of more 21 per cent, the best in Sydney.

Godolphin started working on visas for Buick last week after Doyle visited a doctor in Dubai about his knee and was advised to see a surgeon.

William Buick riding Francis Of Assisi wins race 3 the Queen Elizabeth Stakes on Stakes Day at Flemington last year. Photo: Michael Dodge

"It is an advantage to know William can come out here and he will able to get on a few of these horses in the lead-up to Golden Slipper day," O'Shea said.

"He will have the first choice on our rides on Slipper day, if Doyle is not available. He will ride either Veranillo or Trekking in the Golden Slipper, Hauraki in the George Ryder Stakes and Hartnell in the Ranvet Stakes.

"It is such an important day for us and we have some really good group 1 chances. It is good to have the confidence that we will have William on them.

"We will still using other jockeys like Brenton Avdulla, who has been doing a good job for us. "

O'Shea confirmed star three-year-old Astern would not start in the Galaxy and would go first-up in the TJ Smith during The Championships.

It is hoped that Doyle may be fit for the Championship but Buick is likely to come for the two meetings at Randwick in April, where he will be used by Godolphin's Newmarket-based trainer Charlie Appleby. He will not be able to ride in Sydney on BMW day on March 25 as it coincides with the Dubai World Cup meetings.

O'Shea was pleased with the effort of Trekking when Black Opal runner-up, particular his last 100m and believes it will improve into the Golden Slipper at Rosehill on March 18.

"He is in the Slipper now and will take a fair bit of benefit from that run." O'Shea said.

Godolphin will attempt to qualify Alizee and Coruscate in the final Slipper trials on Saturday.

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