Dual Classic-placed Galileo Rock is one of 43 entries for the St Leger at Doncaster on September 14.

Third in the English Derby and second in the Irish equivalent, David Wachman's colt is 5-1 joint favourite along with the Aidan O'Brien-trained Leading Light.

Galileo Rock's three-parts brother, Saddler's Rock, landed the Doncaster Cup at the 2011 meeting and Wachman said: "We are definitely thinking about the St Leger for Galileo Rock.

"He has come out of his run in the Irish Derby fine and there is not a bother on him.

"I suppose that his second behind Trading Leather was his best run to date, although his run at Epsom wasn't too bad either. The Irish Derby was a good race and we will see how the form stacks up when the winner runs in the King George this weekend.

"Galileo Rock's pedigree suggests that he is going to get better with age and we are hopeful that he can keep improving.

"The St Leger is still a long way away and there is no rush to decide where he runs next - we will make up a plan as we go along."

O'Brien, who was narrowly denied a clean sweep of English Classics and an historic Triple Crown last year when Camelot could only finish second to Encke, has 12 entries headed by Queen's Vase winner Leading Light, Irish Derby third Festive Cheer and Epsom fourth Battle Of Marengo.