LOUISVILLE, Ky. (AP) -- Trainer Larry Jones says Mark Valeski will not run in the Kentucky Derby on Saturday, clearing the way for D. Wayne Lukas' Optimizer to join the 20-horse field.

Jones says the horse that's named for a friend of owner and former Kentucky Gov. Brereton Jones wasn't training well enough to win. Larry Jones says he felt the bay colt was Derby quality, but he wouldn't be ready for Saturday's race.

"We really were looking for a `wow' work and we don't think Mark gave us that feeling," Jones said. "When you go in, you've got to be ready to tackle the bears. This is the Derby."

Mark Valeski was 19th on the graded stakes earnings list with $260,000 and had finished second in both the Risen Star Stakes and the Louisiana Derby at Fair Grounds in New Orleans. Jones said he'll next run at the Peter Pan Stakes at Belmont Park and could run in the Belmont Stakes after that.

"We want other things from Mark down the road," Jones said. "Two weeks from now we may have that Derby horse and he may still show up at the Belmont. It's just not worth it right now. I think he's going to get better."

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