Racing: Deck shuffled in Kentucky Derby

Improbable has moved into second favouritism for the Kentucky Derby tomorrow. Photo / AP

Suddenly, the Kentucky Derby is wide open.

Favourite Omaha Beach was scratched because of a breathing problem on Wednesday night, leaving a pair of Hall of Famers on the sideline — trainer Richard Mandella and jockey Mike Smith.

Churchill Downs oddsmaker Mike Battaglia revised the morning line to make Game Winner the 9-2 favorite for the 1 1/4-mile race tomorrow.

Improbable and Roadster were installed as the co-second choices at 5-1, giving five-time Derby-winning trainer Bob Baffert the top three choices in the 20-horse field.

Mandella told the Associated Press that Omaha Beach developed a cough and a subsequent veterinary exam showed the colt has an entrapped epiglottis.

It's generally not life- or career-threatening and is typically corrected with minor surgery.

"It's been a devastating thing, but we have to do what's right for the horse," said Mandella, who has never won the Derby with six previous starters. The trainer said Omaha Beach will have surgery in Kentucky in the next few days and will be sidelined for two to three weeks.

The ordeal will knock him off the Triple Crown trail.

"It's such a disappointment, but we'll fight again," Mandella told the AP. "We won't be out a long time."

The scratch was another blow to cancer survivor Rick Porter, the colt's 78-year-old owner.

Porter has twice finished second in the Derby, in 2007 with Hard Spun and the following year with filly Eight Belles, who broke her ankles past the finish line and had to be euthanised.

"He's a great sport," Mandella said. "I've got very good support."

Omaha Beach had been the 4-1 early favourite.

Mandella's dry sense of humour came out when he said, "My wife has my leg tied down so I can't jump out of the window."

Smith had chosen to ride Omaha Beach instead of Roadster and now he won't have a chance to win the Derby for the second straight year.

He rode Justify to victory last year.

"I'm a little bummed out, but the horse is okay and we're going to be all right," Smith said. "The good news is it wasn't anything that is life-threatening."

- AP