Kingsbarns is still reported to be on course for the Derby despite being a major doubt for the 2000 Guineas at Newmarket.
Aidan O'Brien's Racing Post Trophy winner suffered a setback which caused him to miss a racecourse gallop at the Curragh two weeks ago.
"He had a stone bruise, he is only back in light work now and he is getting better," the trainer's jockey son, Joseph, said.
"He was working very well before his setback and we thought he would be back for the Curragh (the gallop on the opening day of the season).
"The Guineas is looking unlikely now but there is no reason he won't be ready for the Derby."
The Jim Bolger-trained Dawn Approach is hot favourite for the Newmarket Classic on May 4 and connections have not ruled out adding him to the field for the Derby at Epsom on June 1.
"Sheikh Mohammed suggested to enter him in the Derby after his win in the Dewhurst," Bolger said.
"His pedigree suggests he won't get the trip but he switches off so well I wouldn't rule it out."