Eclipse Award champion Acclamation has been diagnosed with a "mild strain" in a ligament in his left front pastern, his connections reported Thursday.
The six-year-old Unusual Heat horse had been pointing for a title defense in the TVG Pacific Classic Stakes (G1) at Del Mar on August 26 before he emerged from a Monday gallop with slight swelling in the ankle.
"It's not serious. It's not career-ending, at least we don't think so right now," owner E.W. "Bud" Johnston said. "But it's something that makes it impossible to train on it for a short period of time at least.
"We've been very fortunate with him and we were really looking forward to the race. But we're hoping that maybe we can meet those guys in the Breeders' Cup."
Johnston did not indicate when Acclamation might return to training or racing.
"We have to keep a close watch, and he'll tell us when he's ready," Johnston said. "We can't say one way or the other, but he's not lame or anything, he's acting fine this morning, and I think he'll be back."
Acclamation, trained by Don Warren, has won seven consecutive races, including the Charles Wittingham Memorial Handicap (G1) and Eddie Read Stakes (G1) to start this year. The horse also won both events last year, along with the Pacific Classic, en route to the Eclips