Astern's much-anticipated return to racing risks being delayed with trainer John O'Shea confirming Godolphin's star colt will not contest the $2.5 million TJ Smith Stakes if Sydney's weather deteriorates.

Although the sun made a welcome appearance on Wednesday, rain is forecast to return before and during Saturday's opening day of The Championships at Randwick.

The three-year-old, who is expected to go to stud after the autumn carnival, has not raced since finishing second to Flying Artie in October's Group One Coolmore Classic at Flemington because of niggling injuries and viral issues.

Randwick was upgraded to a soft classification as the climate changed for the better this week, but if the track is downgraded to heavy, Astern will be kept on ice until the All Aged Stakes (1400m) at the same track on April 15.

"We just have to hope the rain doesn't come, because if it got to 'heavy' we wouldn't run Astern," O'Shea said.

"Ideally in the heavy ground it's best to have a run somewhere, which he hasn't had."

Astern, who has accrued $1.1 million prize money from eight races, has had three barrier trials, his most recent on a heavy track at Randwick on March 7 in which he ran fifth of seven.

Last year's Group One Golden Rose winner has drawn gate four in the TJ Smith (1200m) and is second favourite ($6) with the TAB behind Hawkes Racing's Chautauqua ($4.60).

O'Shea nominated Russian Revolution, the last-start winner of The Galaxy at Rosehill, as the main danger.

"He's met Russian Revolution ($7) previously and been able to get past him but I think he's the horse to beat," he said.

O'Shea also said wet weather would not do Hauraki any favours in the $3 million Doncaster Mile despite his previous exploits over the distance.

The five-year-old prefers solid footing and unfortunately the Canterbury Stakes - in which he was third - and George Ryder (4th) were run on heavy.

"Unfortunately he hasn't had the best of preps with all his runs being on heavy ground, and it doesn't appear he'll get anything but that again," O'Shea said.

"He'll just be ridden quietly as always and see if he can come over the top of them.

Despite O'Shea's meteorological concerns Hauraki was listed as the joint $9.50 second favourite with the Chris Waller-trained McCreery.

The Kris Lees-trained Le Romain heads the TAB market at $6.