2,000 Guineas: Aidan O'Brien reveals Kingsbarns is doubtful

Irish trainer Aidan O'Brien has revealed the 2,000 Guineas second favourite Kingsbarns is a doubt for the Classic at Newmarket on 4 May.

Kingsbarns, the Racing Post Trophy winner and around a 6-1 shot for the one-mile contest, has a foot infection and missed 10 days of work, including a workout at the Curragh on Sunday.

"You'd have to be worried about him for the Guineas," admitted O'Brien.

Dawn Approach, trained by Jim Bolger, is the 2-1 Guineas favourite.

Bolger enjoyed a successful first day of the Irish season with four winners: Saburo, Caesaria, Rehn's Nest and Derby entry Alpinist.

The County Kilkenny-based trainer won the 2008 Derby with New Approach.