Winston has ridden 98 winners so far this season

It means the Irishman's dream of a first title is almost certainly over.

His mount Pearl's A Singer fell on the home bend, bringing down other horses, and Winston went through the rails.

"I think you are looking at anywhere between two and three months at the quickest to get back," said his agent Richard Hale.

Winston, who led the title race with 98 winners, just ahead of Jamie Spencer, will undergo an operation on Sunday at Crosshouse Hospital, Kilmarnock.

He sustained two fractures on his lower jaw and possible fractures on the upper jaw in the incident which led to the remainder of the meeting being abandoned due to unsafe ground.

"Robert is taking the view that he will take the rest of the year off a try and come back at the turn of the year," said Hale.

"Whether he rides in Dubai or on the all-weather over here, he's not going to rush back. He's got a lot of damage to his teeth and all that will need to be sorted out.

" I think he's just relieved he's still talking to us because it was a hell of a fall. It could have been a lot worse. He got a real bash in the face but he could have been left unconscious.

"You have got to look on the bright side - he will be back for next season and have a go."

Bookmakers have now installed Jamie Spencer as the odds-on favourite to be crowned champion with Seb Sanders next in the betting.