Top sprinter Deacon Blues has been ruled out for the season due to injury, according to trainer James Fanshawe.
Scans taken on Saturday showed the deeply progressive five-year-old sprinter to have sustained a tear to a tendon in a leg.
Fanshawe said: "We discovered some unusual warmth in his left-fore leg on Friday evening.
"We had him scanned on Saturday and we found a small tear in a tendon, which I'm afraid rules him out for the season."
Deacon Blues was named last season's joint-champion sprinter of Europe after winning five consecutive races, including the Wokingham Stakes at Royal Ascot and the Phoenix Sprint Stakes at the Curragh.
He signed off for the year with an outstanding length-and-a-half success in the Qipco British Champions Sprint Stakes at Ascot in October.
Fanshawe hopes the son of Compton Place will still be able to return to a racecourse in 2013.
He added: "It's a big blow for the yard and his owners, but with injuries like this you cannot rush them.
"The main thing is to give him every possible chance of a full recovery."