Leading fancy Maybe appears unlikely to take her place in Friday's Coronation Stakes at Royal Ascot despite being declared.
Aidan O'Brien's filly was third in the 1000 Guineas at Newmarket before finishing fifth in the Oaks and she was expected to go close back over a mile on Friday.
The three-year-old is one of 12 declared fillies for the Coronation Stakes, but looks set to miss out after suffering a setback. O'Brien's wife Annemarie tweeted: "Maybe is a doubtful runner in Friday's Coronation Stakes due to a stone bruise."
O'Brien still has a major contender for the race in 1000 Guineas heroine Homecoming Queen, who was last seen finishing fourth behind Samitar in the Irish Guineas.
The latter reopposes for Mick Channon and is once again ridden by young jockey Martin Harley.
Channon also has a strong second-string to his bow in the shape of Laugh Out Loud, who ran out an easy winner of a Group Two in France last time out.
John Gosden is treble-handed with Elusive Kate, Fallen For You and Starscope.
William Haggas runs the once-raced Cardigan with Chris Wall's Intense Pink, the Sir Michael Stoute-trained Russelliana and the sole French challenger Bugie D'Amore completing the line up.