Kentucky Derby winner California Chrome is shining even brighter heading into today's Preakness Stakes, the second leg of US flat racing's triple crown.

"I think he loves it," assistant trainer Alan Sherman said of the adulation the chestnut colt has received since arriving this week at the Pimlico racetrack in Baltimore, where the US$1.5 million, one and three sixteenths of a mile Preakness will be run.

It's an awesome feeling having a horse of this calibre
Alan Sherman

The glow around Chrome dimmed a bit on Thursday, when word went round he had been seen by a vet, but his connections quickly moved to dispel any concerns, saying the colt had a small blister in his throat that was not serious.

"He's fine," said Alan Sherman, son and assistant to trainer Art Sherman. "It's not a big deal."

California Chrome's emphatic Kentucky Derby triumph on May 3 has made almost everything about him a big deal, and if he wins in the field of 10 things will only get bigger.

That would give him a chance to become the first horse since Affirmed in 1978 to sweep the coveted treble of the Kentucky Derby, Preakness and Belmont Stakes - with the last race of the trifecta coming on June 7 at Belmont Park in New York.

"It's an awesome feeling having a horse of this calibre," Alan Sherman said. "It's the first time we've had a horse this good."

California Chrome comes complete with an appealing story of humble beginnings, bred by owners Steve Coburn and Perry Martin from an US$8,000 mare that they matched for US$2,000 with an undistinguished stallion.

But after five victories in his last five starts by a combined 26 lengths, Coburn is not afraid to predict that California Chrome will be the first horse in 36 years to pull off the triple crown.

California Chrome is an odds-on 3-5 favourite to add the Preakness to his résumé.

Kentucky Derby winners have run well in the slightly shorter Preakness. Since Affirmed won the triple crown, a dozen horses have won both other races only to falter at Belmont.

Since 1997, eight Derby winners have won the Preakness, and California Chrome's jockey Victor Espinoza rode one of them - War Emblem in 2002.

He will break from gate three under Espinoza, and is likely to confront early speed.

"He'll do whatever Victor asks him," Alan Sherman said. "He's pretty good that way."

Only two other horses from the Derby field will line up in the Preakness: Ride On Curlin and General a Rod.

Ride On Curlin finished seventh at Churchill Downs after a tough trip under Calvin Borel, and trainer Billy Gowan has replaced Borel with Joel Rosario, who won the 2013 Kentucky Derby aboard Orb.

Gowan said Curlin had bounced back well from the Derby. "He's one tough horse. Hopefully, we can turn the tables," he said.

Among the seven new challengers, few look to pose any major threats, apart from Social Inclusion, who is expected to set the pace and, after drawing gate eight, was installed as the second choice at 5-1.

The lone filly will be 2013 Breeders' Cup Juvenile Fillies winner Ria Antonia. Trained by Tom Amoss, she will start from post six, with Borel aboard.