Hall of Famer D. Wayne Lukas is the new trainer for 2009 Kentucky Derby winner Mine That Bird.
Chip Woolley Jr., who trained the gelding to a 50-1 upset in last year's Derby, said the horse has been sent to Lukas' barn at Churchill Downs.
Mine That Bird has been resting in New Mexico for several months following a grueling 3-year-old campaign that included one of the biggest upsets in Derby history.
Jockey Calvin Borel piloted Mine That Bird through the slop at Churchill Downs to win by 6¾ lengths.
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Woolley said he was "devastated" by the decision but will continue to train other horses for Mine That Bird's owners, Leonard Blach and Mark Allen.
"A guy's got to feel like after winning the Derby you'd get your horse back but I guess, you know, apparently I didn't do enough," Woolley said.
Allen did not immediately return a phone call from The Associated Press, but Woolley said the decision to switch trainers wasn't made by his longtime friend.
"I don't think Mark wanted to move the horse at all, period," he said.
Woolley and Allen became folk heroes after last year's Derby and their unlikely path to Churchill Downs became the stuff of legend. They met in a bar fight 25 years ago, and the two self-proclaimed cowboys from New Mexico played in stark contrast to their more refined Derby counterparts.
Woolley hobbled around Churchill Downs the week before the Derby on crutches, the result of a motorcycle accident. His trademark black hat and horseshoe mustache made him instantly recognizable.
Mine That Bird's bid for a Triple Crown ended two weeks later when he finished second to the filly Rachel Alexandra in the Preakness, followed by a third-place finish in the Belmont.
Mine That Bird's 3-year-old campaign ended with a disappointing ninth in the Breeders' Cup Classic at Santa Anita.
Woolley said he's not sure when Mine That Bird will return to racing. He hinted before this year's Derby that it probably wouldn't be until the middle of the summer.
"He's put on a lot of weight and looks super, just super," Woolley said. "I expect great things from him in the future."
Snow Chief dies at 27
Snow Chief, the winner of the 1986 Preakness Stakes, died Saturday in Paso Robles, Calif., from an apparent heart attack at the age of 27.
Snow Chief also won the 1986 Florida Derby, Santa Anita Derby and Jersey Derby.
He was the 2-1 favorite in the Kentucky Derby but finished 11th to Ferdinand.