Kentucky Derby winner Nyquist, expected to face Preakness winner Exaggerator in the June 11 Belmont Stakes, remained stabled at Pimlico Race Course on Monday with a fever.
Dennis O'Neill, brother of trainer Doug, told BloodHorse that Nyquist's body temperature was 102 degrees Fahrenheit; a normal temperature is 99 to 101 degrees.
"I think he has some sort of virus we need to get under control," O'Neill said. "He ate well but his temperature was 102 so we decided not to ship. We drew some blood and will know more tomorrow."
Doug O'Neill had planned to ship the colt, who finished third in Saturday's Preakness, to New York for the final leg of the Triple Crown. O'Neill told The (Louisville) Courier-Journal that there's no timetable for Nyquist's return to training or move to New York.