Ron the Greek, the morning line choice for the $5 million Breeders' Cup Classic, was scratched from the race on Thursday because of a hoof injury, his Hall of Fame trainer Bill Mott has said.
"Unfortunately, we're going to have to scratch him," Mott said in a statement. "He had an abscess that broke open in his foot.
"It's not a major problem, but it's all a matter of timing and he won't be able to run on Saturday."
Ron the Greek was fourth in the 2012 Classic and was in good form having produced a smashing effort on September 28 to win the Jockey Club Gold Cup at Belmont Park.
The five-year-old has won nine career races, including two this year.
The abscess in his right front foot was discovered on Wednesday.
"When he came out to walk is the first we recognized any problem," said Mott, who won the 1995 Breeders' Cup Classic with Cigar and the 2011 race with Drosselmeyer. "That horse has been doing fine. He's never had foot issues before in his life.
"He had a strong gallop yesterday and he must have just bumped the heel of his foot wrong and he got an abscess in the bulb of his heel.
"We soaked him and it opened up and relieved some of the pressure late yesterday afternoon but he was still sore on it this morning and I just made the determination that we couldn't have him good enough to run on Saturday."
(Reporting by Steve Keating in Toronto; Editing by Greg Stutchbury)