Ayrton’s spring campaign is under a cloud after the boom four-year-old was found to be lame.

Co-trainer Mick Price informed Racing NSW stewards on Thursday that Ayrton had swelling to his near hind leg but the extent of the issue was unclear.

“Mr Price has advised that Aytron has been treated by his stable veterinarian, however, at this point in time there is no conclusive diagnosis,” Racing NSW stewards said in a statement.

Ayrton is a pre-post $4.50 favourite for the Group 1 Epsom Handicap (1600m) at Randwick on October 2 and is also prominent in early markets for the Golden Eagle.

Price says the stable will continue to assess Aytron’s health and will update stewards on his condition in the coming days.

The winner of five of his seven starts, Ayrton resumed with 1400m victory at Caulfield last month before finishing third behind Harbour Views and Cherry Tortoni in Listed grade at Flemington on Saturday.