The trainer of I'll Have Another was suspended Thursday but will not miss the Belmont Stakes.
Doug O'Neill was suspended 45 days after one of his horses was found with a performance-enhancing mixture in its system after a race in California in 2010.
The punishment won't begin before July 1, meaning he can be at the Belmont on June 9.
Racing officials said they believe O'Neill did not give the horse the illegal mixture but trainers are ultimately still responsible for horses in their care.
I'll Have Another will try to become the first horse to win all three jewels of racing's Triple Crown since Affirmed in 1978.