California Chrome might abandon his Triple Crown bid in the Belmont Stakes if New York officials do not allow the colt to wear a nasal strip.
Trainer Art Sherman suggested it was a possibility, although he made no threats about California Chrome passing on a chance to become horse racing's 12th Triple Crown winner.
The Kentucky Derby and Preakness winner has worn a nasal strip during his current six-race winning streak after co-owner Perry Martin wanted to try it.
Sherman is based in California and said he wasn't aware that using one in New York might be a problem.
He said he would talk to New York racing officials and the horse's owners.
Some horses, like humans, wear nasal strips to assist breathing.
The colt wears the strip only during races, not training.
At 1 1/2 miles, the Belmont on June 7 is the longest and most grueling of the three Triple Crown races.