Keen Ice retired to stand at Calumet Farm

Keen Ice, the last horse to beat US Triple Crown hero American Pharoah and a general 33-1 chance for next week's Breeders' Cup Classic, will not run in the race after suffering an injury.

Trained by Todd Pletcher, Keen Ice was due to be retired after the Classic, but has been denied a third crack at it and will be retired to stud at Calumet Farm in Kentucky.

"He's got a wrenched ankle and there's not time to let it quiet down," Pletcher told the Daily Racing Form.

"We've got to breeze now, trying to make a race on the other side of the country against the best horses in the world. It's not shaping up right. He's accomplished everything he's accomplished, he's already got a home at Calumet, so hopefully he goes on and has a successful stallion career."

A son of Curlin, Keen Ice, who began his career with Dale Romans, chased home American Pharoah in the Kentucky Derby, Preakness and Belmont Stakes in 2015 and got his revenge on Bob Baffert's star with a shock victory in the Travers Stakes that year.

American Pharoah set the record straight months later in the Classic with Keen Ice fourth, a place he bettered when third to Arrogate 12 months ago.