Triple Crown winner American Pharoah is on his way to the Travers Stakes at Saratoga where a sell-out crowd is likely to turn one of racing's most historic tracks into a festival to remember.

"Saratoga here we come!" owner Ahmed Zayat said on Sunday, moments after American Pharoah came off the track following a work-out at Del Mar in California.

Before making the long-awaited decision to run in Saturday's Travers in New York, Zayat and trainer Bob Baffert wanted to wait until this final gallop - seven furlongs (1400m) in 1m23.20s.

"He's showing zero wear and tear. In fact he's more mature, even getting better," Zayat said.

"He did it so easy, the exercise rider couldn't even pull him up. Bob needed to see that."

About 2000 fans showed up to watch American Pharoah gallop.

"He always works well, but we wanted to make sure if he still has that energy level," Baffert said. "It was an incredible work, though. He is a pretty incredible horse."

Weeks ago, New York racing officials capped the crowd at 50,000 for Travers day in anticipation and all tickets are sold.

If American Pharoah starts, the purse increases by $US350,000 ($A479,912) to $US1.6 million ($A2.19 million).

The horse is scheduled to arrive at Saratoga on Wednesday.

American Pharoah is the first horse in 37 years to sweep the Kentucky Derby, Preakness and Belmont Stakes. He has since won the Haskell Invitational in New Jersey on August 2.

Now he will attempt to do something that hasn't happened in 74 years.

Of the previous 11 Triple Crown winners, only three ran in the Travers, and just one - Whirlaway in 1941 - came away a winner.

American Pharoah has won eight straight races after a loss in the first start of his career. The game plan is for a final race in the $5 million Breeders' Cup Classic on October 31 at Keeneland in Lexington, Kentucky. And then it's off to the breeding shed a few miles down the road at Coolmore's Ashford Stud.