King Fury, who appeared to be on his way to the Preakness Stakes after scratching from the Kentucky Derby because of a fever, will also miss the second leg of the Triple Crown.
Racing publicist Jennie Rees said in a Twitter post that the fever has returned and that the Curlin colt also has developed a cough.
McPeek told Horse Racing Nation that "he's still not 100 percent. So it's pretty much a no brainer. He's a no-go."
King Fury earned his way into the Kentucky Derby with a win in the Lexington (G3) and a few defections above him on the leaderboard. But he was scratched the day before the race.
"He's not bouncing back as quickly as we'd hoped," McPeek said. "But we'll sort through it, let him tell us."
McPeek confirmed that his "ultimate goal this summer is the Travers." The Grade 1 race will be on Aug. 28 at Saratoga.