Triple Crown winner American Pharoah is expected to have three more races before he is retired to stud.

The colt became just the 12th horse, and the first in 37 years, to win the Kentucky Derby, Preakness Stakes and Belmont, providing an energising jolt to a sport struggling to stay relevant in the United States.

Before he won the Belmont on Saturday (Sunday AEST), passing the 1-1/2-mile (2400m) "Test of the Champion" with flying colours, his owner Ahmed Zayat sold the breeding rights to Ireland's Coolmore Stud in a deal thought to be worth more than $20 million.

But before he takes up duties at Coolmore's Ashford Stud in Kentucky, Zayat says he wants the horse to spread a little more magic among US racing fans.

"We owe it to the sport to do the right thing," Zayat said.

"Money plays an important factor in this game. I've already sold the breeding rights, but it is my genuine desire, as a fan, as someone who loves horses, to race him as long as I possibly can."

He said trainer Bob Baffert would map out the plan for the remainder of American Pharoah's 2015 campaign.

Baffert said his key goal was to have the three-year-old ready to win in his next start.

"I've seen Triple Crown horses come back and get beat," Baffert said. "I don't want that to happen."

The 62-year-old trainer said he thought American Pharoah might be ready to race in as little as two weeks and three more races this year was a reasonable goal.

That raises the prospect of a mouth-watering start in the $5 million Breeders' Cup Classic, which will be run this year at Keeneland in Lexington, Kentucky, on October 31.