Marco Botti still hopes Tac De Boistron can defend his Prix Royal-Oak title at Longchamp in October after ruling him out of his next two targets due to a rib injury.

The trainer had planned to run him in the Irish St Leger at the Curragh in September and the Prix du Cadran at Longchamp a few weeks later.

The Australian Thoroughbred Bloodstock-owned seven-year-old is suffering from bruised ribs but the damage is not serious.

"He's going the miss the Irish St Leger and the Cadran," Botti said.

"I hope he'll be fine for the Prix Royal-Oak.

"It was just a freak accident, he fell over outside and bruised his ribs but they are not broken.

"He's been for a bone scan and it just showed they are tender and we can't put any tack on him.

"Usually it takes two or three weeks to heal."

The gelding returned to Europe after a Melbourne Cup preparation for Victorian trainer Mick Kent in 2012 when he failed to handle firm tracks.