Aidan O'Brien has admitted Air Force Blue "is only a shadow of what he was" following another poor performance at the Curragh on Sunday, his fourth of the season.

The War Front colt was crowned last season's champion two-year-old after completing a hat-trick of Group 1 victories in the Dewhurst at Newmarket and was odds-on to make a winning return and claim classic glory in the 2000 Guineas.

However, he was bitterly disappointing at Newmarket, and then fared little better in the Irish 2,000 Guineas and, although he met trouble in running in the July Cup, a drop in grade for the Phoenix Sprint Stakes at the weekend failed to yield any improvement as he trailed home last of seven runners.

O'Brien said: "We'll see how he is. Obviously we'll talk about it over the next week. It was a very disappointing run. He never really took off and is only a shadow of what he was."