The weight-for-age championship of the spring is near the top of the list of races  Coolmore wants to win in Australia, its  desire further fuelled by losing champion mare Atlantic Jewel through injury only days before last year's Cox Plate, when an odds-on favourite.

Coolmore Australia will target the Cox Plate with a group of Fastnet Rock  three-year-old colts, including Zululand, Wilderness and Valentia, who  will be among the entries when they close on Tuesday, but it will be Ballydoyle's willingness to enter Adelaide that  will cause a surprise.

"I can confirm Adelaide has been entered for the Cox Plate," Coolmore Australia's racing manager James Bester said on Sunday. "They are still discussing if there will be any entries in the Caulfield and Melbourne Cups and I'm waiting to hear from Ballydoyle."

O'Brien had success bringing a Northern Hemisphere three-year-old to Melbourne for the spring when Mahler ran third to Efficient in the  Melbourne Cup seven years ago. However he hasn't returned since the controversial 2008 Melbourne Cup 12 months later when he was hauled back to Flemington from the airport to answer questions about the tactics and performances of his three runners.

The Moonee Valley Racing  Club would be delighted to get the entry for Adelaide, perhaps Ballydoyle's second-best three-year-old behind English and Irish Derby winner Australia, and would be expected to add him to the international invitee list it released in June.

That list of 10 included some of the best turf horses in the world. Dubai Duty Free and Tenno Sho winner Just  A Way, Dubai World Cup victor African Story, six-time group 1 French champion Cirrus Des Aigles and Frankel's little brother Noble Mission were on the wish list but won't be coming.

The only horse to take up the invitation is Singapore International Cup winner Dan Excel from the Hong Kong yard of John Moore, who has already arrived in Australia and is preparing from the Rosehill stable of Moore's brother Gary.

Adelaide has not missed a place in five starts and was runner-up in the Edward VII Stakes at Royal Ascot, which is often referred to as the Ascot Derby, and last month's Belmont Derby International Stakes.

He is due to have another start in America in the group 1 Secretariat  Stakes over about 1900m on Arlington Millions day in Chicago on August 16, after which a decision on whether to come to Australia will be made.

Entries for the Melbourne Cup and Caulfield Cup also close on Tuesday and  indication are there will be strong international influence.

Coolmore is also hoping to have at least one of its three-year-olds stand up during the spring and make it to Cox Plate.

As well as Valentia, Wilderness and Zululand there is also four-year-old Bull Point, now trained by Chris Waller, who is targeting the Sir Rupert Clarke Stakes at Caulfield in September.

"Valentia, Zululand and Bull Point are group-winning sons of Fastnet Rock, which makes them stallion prospects and we are hoping they can take the next step to group 1 level this spring," Bester said.

"David Hayes is going to nominate Zululand and Wilderness, which broke his maiden at Geelong on Friday, for the Caulfield Guineas and Cox Plate, as will Gai Waterhouse with Valentia. They are also in the Golden Rose.

"They have to prove they are good enough to get to that level but it is exciting to have horses that have improved from two to three and that are only going to get better.

"At the moment, we would hope that one or two of them might be ready for the Golden Rose but Zululand and Valentia look like being mile [1600 metres] and beyond types."

Zululand and Valentia, who has had two barrier trials, will start their campaigns in coming weeks leading to the Caulfield Guineas. Coolmore also has a share in Rubick, who Gerald Ryan hopes to get  to the Coolmore Stud Stakes on Victoria Derby day despite having to turning him out because of a virus this week.

Bull Point, who was a remarkable third to Zoustar in the Golden Rose last year after being tailed off early, will have his third barrier trial under the care of Waller at Rosehill on Monday.