Kentucky Derby hopeful Gronkowski will miss next week's Run for the Roses.

Phoenix Thoroughbreds said Gronkowski spiked a fever over the weekend and was immediately treated with antibiotics. While the sudden illness seems minor and the colt has been eating heartily and otherwise responding well to treatment, the condition will prevent his shipment to Louisville, according to a news release from Churchill Downs Racetrack.

"We are beyond disappointed that Gronkowski will miss the Kentucky Derby," Tom Ludt, who directs Phoenix's international operations, said in the release. "To have a Derby contender with our first group of three-year-olds was a dream come true, and to have had New England Patriots star Rob Gronkowski join us on that journey made it even more exciting. But we must put the welfare of the horse first and we will look forward to the colt recovering quickly and to his future races."

Gronkowski, who is undefeated in three starts this year, will be given time off from training to fully recover from the illness.

By winning the Burradon Stakes at Newcastle racecourse in England on March 30, Gronkowski earned the first European slot in the Kentucky Derby under the points system created by Churchill Downs. Trained by Jeremy Noseda, he was to be ridden in the Derby by regular jockey Jamie Spencer.

Just a few days prior to the onset of the colt's illness, New England Patriots tight end Rob Gronkowski — for whom the horse was named — took an ownership stake in the horse and had planned to visit him and the Phoenix team at Churchill Downs during Derby week festivities.