King Guillermo was declared out of the Sept. 5 Kentucky Derby Presented by Woodford Reserve (G1) after developing a fever, trainer Juan Carlos Avila tweeted in Spanish Sept. 3. His announced defection leaves a field of 17 for the 1 1/4-mile classic.
The Uncle Mo 3-year-old colt did not train Thursday morning at Churchill Downs and told Blood Horse that the horse had a "little problem" that would require time over the course of the day to evaluate before a decision on his Derby status was finalized. That time eventually came around 4:30 p.m. ET.
Translated via Google, Avila tweeted that "unfortunately we will not be this Saturday at the (Kentucky Derby). A fever yesterday afternoon took us away from this great dream."
In a follow-up tweet, he thanked the support of the public and mentioned the Preakness Stakes (G1) at Pimlico Race Course as a next goal for the colt.
Earlier this morning, Avila said, "It's a big race and a little problem is a big problem for me," a reference to the timing two days before the Derby.
King Guillermo has not raced since finishing second to Nadal in a division of the Arkansas Derby (G1) May 2 at Oaklawn Park. Before that effort, the son of Uncle Mo delivered an upset victory in the Lambholm South Tampa Bay Derby (G2). He has been training at Churchill Downs for more than a month after traveling from his regular base in Florida.
The colt is owned by retired Major League Baseball All-Star Victor Martinez, who races under the stable name Victoria's Ranch.