It's all hands to the pumps in the Aidan O'Brien camp for a big international Group One weekend that will be headed by Scorpion in Sunday's Prix de l'Arc de Triomphe.

Ahead of this morning's supplementary stage there are 15 intended starters for the Arc, and the Ballydoyle trainer has confirmed his St Leger winner will be among them. "The plan is to run subject to everything being okay with him later in the week," O'Brien confirmed yesterday.

However, with Kieren Fallon set to team up with the ante-post favourite, Hurricane Run, the way has been left clear for the former Ballydoyle number one Michael Kinane to be called up for the ride on Scorpion.

Kinane, who returns to action at Newmarket today after five weeks on the sidelines with a fractured wrist, will also be reunited with O'Brien for tomorrow's Middle Park Stakes ride on Art Museum as Fallon has opted for the Prix Morny runner-up Ivan Denisovich. O'Brien bids for Group One honours with his filly Beauty Bright in the Cheveley Park Stakes at Newmarket this afternoon but Mick Channon's Flashy Wings will be hard to beat.

Ballydoyle's international focus won't be just concentrated on France and Newmarket as Ace will fly the O'Brien flag in New York on Saturday night. Ace, who has yet to win this season but has been running well in the very top company, is set to run in the Grade One Joe Hirsch Turf Classic Invitational over a mile and a half at Belmont Park.

The controversial Californian-based jockey Pat Valenzuala has been drafted in for the mount on Ace in a $750,000 event that is a traditional warm-up for the Breeders' Cup Turf, which will be held on the same course and distance next month.

Irish trainers are set to be heavily represented at Longchamp at the weekend, with John Oxx's Caradak likely to lead the assault on the Saturday's Group One Prix de la Foret. Caradak has had a break since scrambling home in the Desmond Stakes over a mile last month and is likely to be better for the return to seven furlongs. On Saturday the Oxx team are also targeting the Group Two Prix Dollar with Alayan, while the Park Hill runner-up, Kastoria, is a possible for the Prix de Royallieu.

The home action on Sunday will be at Tipperary, where the John James McManus Memorial Hurdle could see the return to action of last season's Champion Hurdle runner-up, Harchibald. A total of 11 entries remain in the two-mile contest, including Solerina, Ansar and Accordion Etoile.

However, Noel Meade indicated yesterday he will allow Harchibald take his chance if the ground doesn't turn too soft.

"If it's good or yielding I would imagine he will run. But he wouldn't like it too soft or heavy," Meade said.

"He is not fully wound up yet obviously but he is ready for a race."

The flat feature at Tipperary will be the Coolmore Home of Champions Concorde Stakes over seven furlongs, and a 23-strong entry includes the French Guineas runner-up Indesatchel as well as Dermot Weld's Miss Mambo, who ran fourth to Attraction in the Matron Stakes at Leopardstown.

Thurles hosts a mixed card this afternoon and Zelkova looks a decent bet to be an appropriate winner of the three-year-old hurdle.

Frances Crowley's horse was a Fairyhouse winner on the level last month and his flat rating indicated there would be little problem with him also becoming a winner over flights.

A Listowel debut last week did little to change that view as Zelkova ran on noticeably well from the rear of the field to ultimately finish a six-length fourth to Son Of Mary. With that experience under his best Zelkova should be hard to beat now.

Kinger Rocks is another who has been mixing disciplines and a return to the level for the October Race should hold no terrors for Dermot Weld's runner.

John Oxx is heavily represented in the mile-and-a-half maiden, with the well bred Ebaza possibly the best of them.

When it comes to breeding, however, few horses in the country can stand comparison with Sea Of Moyle, a son of Giant's Causeway and the Oaks winner Shahtoush.

He made a belated debut at Listowel last Friday and although eventually beating only four home, Sea Of Moyle didn't get the run of the race at all and looked very green. It looks significant that Aidan O'Brien gives him such a quick reappearanceand the hint should be heeded.