Incurable Optimist, the American-trained horse being aimed at the Irish 2,000 Guineas, has suffered a tendon injury and is unlikely to run this season.

Trainer Dave Donk has revealed the extent of the setback which happened when the colt worked at Gulfstream Park, Florida, on Thursday.

"He came back from a gallop and cooled out just fine, but shortly after we noticed some inflammation in the tendon, which he must have rapped somewhere along the line," he said.

"Any injury to the tendon is considered a bow and this is going to put him out of commission for quite a while.

"We'll give him plenty of time off. All plans we had are off the books at the moment and he probably won't be back until next winter or spring."

Incurable Optimist, bidding to be the second US-trained horse to win the Irish colts' Classic after Leo O'Brien's Fourstars Allstar in 1991, was considered the best three-year-old turf performer in the country.

After switching to turf last year, the son of Cure The Blues was unbeaten in four starts, which included Belmont Park's Grade Three Pilgrim Stakes and Hollywood Park's Grade Three Generous Stakes.

He had been expected to begin his build-up to the Curragh in the Everglades Stakes at Hialeah next month.

Meanwhile, Rough Quest is none the worse for an injury scare at Haydock on Saturday. The 1996 Grand National winner was pulled up by Mark Bradburne after jumping the second fence in the Walrus Hunters' Chase.

The 13-year-old, sent off the 6 to 4 favourite to win on his first outing for 315 days, appeared to sustain an injury when he slipped on the flat before jumping a fence. He was taken back to the stables in a horse ambulance.

But following an examination, the lameness appeared to have gone as the horse was able to trot round the stable yard.