Imperative will not run in the Breeders' Cup Dirt Mile on Nov. 3 at Del Mar owing to "what appears to be the beginning of a hairline fracture of the pelvis," his trainer, Bob Hess Jr., said Saturday.

"It'll heal. He'll be fine. But he's out of the race," Hess said. "I don't think it will be career-threatening."

Imperative would have been making his first start since April in the Dirt Mile. He had a small leg fracture that necessitated time off then. He worked earlier this week on Thursday at Del Mar in a situation that caused a California Horse Racing Board investigation owing to the work occuring a day before it should have been allowed because Imperative had been placed on the vet's list for shock-wave therapy treatment.

Imperative, 7, has won 6 of 38 starts and nearly $3 million.