Triple Crown winner American Pharoah has been confirmed as a starter in the Group One Haskell Invitational.

Owner Ahmed Zayat said on Thursday the decision to run in the 1-1/8-mile (1700m) at Monmouth Park on August 2 was based on several factors, the most important being the health of his horse, the first to win the Kentucky Derby, Preakness and Belmont Stakes since Affirmed in 1978.

Trained by Bob Baffert, American Pharoah had his first timed workout on Monday since blowing away the field in the Belmont on June 6, covering three furlongs (600m) in 36.40 seconds at Santa Anita in California.

"We want to do right by him, so he comes first," Zayat said.

"He's told us he's happy. He's gained weight back. He's been paraded, literally, from coast to coast, and Bob said we need to go back to work."

Zayat and his family live in Teaneck, New Jersey, and he's a huge supporter of racing in the state and Baffert has won the race a record seven times.

The Haskell is restricted to three-year-olds and is likely to include many of the horses American Pharoah has already soundly defeated.

Monmouth Park officials have plans in the works to make the day a memorable one. Zayat has already put Bruce Springsteen's name on his wish list. Haskell day tradition features Springsteen's "Born to Run" blaring from the sound system before the race.

"We're overjoyed," Monmouth Park president Bob Kulina said.

"It's a great day for New Jersey racing. It's a great day for racing in general, that this horse is going to continue to run.

"We're getting ready for the biggest day in the history of Monmouth Park."