Aidan O’Brien has cast serious doubt on leading Classic contender Opera Singer’s participation in the Qipco 1000 Guineas.

The daughter of Justify announced herself as a major player for the first fillies’ Classic of the campaign when following up a wide-margin victory in a Curragh Group Three with a devastating display at ParisLongchamp in the Prix Marcel Boussac, storming to a five-length success.

However, speaking at the Curragh on Monday, the master of Ballydoyle explained she may debut for the season on home soil rather than Newmarket having met with a setback.

“Opera Singer is a little bit behind them (the colts) and might not make the English Guineas,” he told Racing TV.

“She had a little setback and had to have two weeks easy. When you have two weeks easy, it is just difficult enough to get to the English Guineas.

“It’s possible but more unlikely than likely and she could end up starting here in the Curragh rather than starting in England. We won’t force her, she’s a beautiful big filly and everyone’s very happy with her.

“She had a couple of easy weeks and when that happens you have to be wary of it.”

In contrast, it appears all systems go for the odds-on Qipco 2000 Guineas favourite City Of Troy who has been pleasing his handler in the early days of his three-year-old season.

O’Brien continued: “Everything has gone very well with him. He’s matured lovely, he’s moving well, he’s going through all his work very well – he’s floating through the work, that’s what he’s doing.

“Even though our ground is bad, he’s finding it very easy, so he’s very exciting. It’s day by day at the moment but we couldn’t be happier with him at the moment.”

Although City Of Troy often left people astonished with the manner of his victories during his flawless two-year-old campaign, it was dual-Derby hero Auguste Rodin who was undoubtedly Ballydoyle’s top performer in 2023.

He signed off his Classic season with a scintillating success at the Breeders’ Cup in Santa Anita and is close to his eagerly-awaited return, where the son of Deep Impact will seek further international riches in the Dubai Sheema Classic.

“He’ll work this week and then he’ll go off to Dubai,” said O’Brien.

“He’s in a lovely place. He was in Dundalk a few weeks ago and everything went lovely, so we couldn’t be happier with him and we’re looking forward to it.

“It’s a big week for him before he travels so hopefully everything goes well.”

O’Brien has also left the door open for Seamie Heffernan after the Ballydoyle stalwart left his full-time role with the powerhouse operation.

The 51-year-old has been part of the Ballydoyle furniture for nearly 30 years and a vital member of O’Brien’s team, winning the Derby aboard Anthony Van Dyk in 2019 and partnering the winner of the Irish equivalent on four occasions for his long-time boss.

But Heffernan has revealed he has chosen to ride freelance this season, with O’Brien fully understanding of the decision.

He said: “I was reading in the papers that Seamus has been riding for us for 25 to 30 years and at the start of every year I never know when Seamus is coming back.

“Obviously himself and Rochelle had a chat and he was always with us six mornings a week and they obviously felt he would like to give the outside world a bit of a chance.

“There are a lot of other people he has ridden for and lots of other people he will now be able to ride for and we totally appreciate it and understand that and respect it in every way. I think Seamus is 51 or 52 now and if he is going to do it now is the time to do it and there will be plenty of times he can fall in for us – he’s got plenty of experience and is a great fella.

“I totally understand it 100 per cent and everyone needs to do what they think is right. There is no point riding for us every day and their heart being somewhere else or thinking he should be somewhere else.

“He has to try things and I definitely couldn’t say it will be the wrong thing. Seamus will ride a lot of good horses, for different people in good races, he has plenty of experience and hopefully there will be plenty of times he will ride for us again as well.”