There’s a curiosity about Big Brown in the Kentucky Derby. Is he really as good as trainer Rick Dutrow Jr. has boasted? Is he the rare favorite who will win? Can he defy tradition by winning off just two prep races?

Those questions and more will be answered Saturday when a full 20-horse field, including filly Eight Belles, runs 1 1/4 miles in America’s greatest race.

The way Dutrow talked leading up to the 134th Derby, there’s Big Brown and a bunch of also-rans in the race.

“Who knows? I don’t think anyone really knows except Dutrow,” said Barclay Tagg, who will saddle Big Truck and Tale of Ekati in pursuit of his second Derby win. “He at least says what he thinks; I’m not knocking him for it. He seems to know what’s going on better than I do.”

Dutrow even dissed Eight Belles, who is 4-for-4 this year.

“I can’t imagine there’s a filly in this world that can beat Big Brown,” he said.

Big Brown is the 3-1 morning-line favorite for the $2 million Derby, having won all three of his races by a combined 29 lengths. He didn’t race as a 2-year-old, challenging the notion that young colts need plenty of seasoning before trying the Derby.

Favorites rarely win the Derby, either; only three have done so since Spectacular Bid in 1979, including Street Sense last year.

Another challenge facing Big Brown is overcoming the No. 20 post on the far outside, something only 1929 winner Clyde Van Dusen accomplished. But Big Brown scored a five-length victory in the Florida Derby leaving from the outside post.

Dutrow has been over-the-top with his confidence, touting Big Brown as the best and fastest horse in the race.

“I just can’t wait until tomorrow when they load him in the gate. He’s a dream come true, seems like he was born for this track,” he said. “I’m sitting on go here, we’re ready.”

A dominant win by Big Brown would renew excitement about a possible Triple Crown champion for the first time since Affirmed swept the Derby, Preakness and Belmont Stakes 30 years ago.

“We could get a standout horse after the Derby, but right now it’s hard to say one of them has star quality,” said Hall of Fame trainer D. Wayne Lukas, a four-time Derby winner. “It’s been a little upside down this year.”

Big Brown isn’t the only horse bucking Derby history.

Colonel John, the 4-1 second choice, only ran two preps this year, along with Court Vision, Monba, Tale of Etaki and Recapturetheglory. Since 1947, only Sunny’s Halo in 1983 and Street Sense have won the Derby with so few preps.

“It’s going to be very interesting,” said Nick Zito, a two-time Derby winner who will saddle Cool Coal Man and Anak Nakal.

Santa Anita Derby winner Colonel John has never been worse than second in six career starts _ all on synthetic tracks made of wax-coated sand, fibers and recycled rubber.

Can Colonel John make the transition to dirt?

“I’ve liked what I’ve seen since I got here and I have no reason to change my opinion,” trainer Eoin Harty said.

Eight Belles will try to become the fourth filly to win the Derby and first since Winning Colors in 1988. She’s never run against the boys before. Trainer Larry Jones will try to sweep the Kentucky Oaks-Derby double, having won the race for fillies with Proud Spell on Friday.

“We think she belongs,” owner Rick Porter said. “Right now, you don’t know how good Big Brown is.”

A 30 percent chance of isolated afternoon thunderstorms was in Saturday’s forecast, with a high of 73. Post time is shortly after 6 p.m. EDT.

A wet track could be good news for Derby long shots Cool Coal Man, Visionaire, Smooth Air and Denis of Cork, all of whom have won over sloppy tracks. Pyro ran second in the Breeders’ Cup Juvenile at muddy Monmouth Park. Tale of Ekati, Big Truck and Z Humor hate the mud.

Nine of the 20 horses are coming off synthetic surfaces, and like Colonel John, Big Black Jack will be running on dirt for the first time.

Louisiana Derby winner Pyro finished 10th in the Blue Grass on Keeneland’s synthetic track, the colt’s first race off the dirt. Pyro is the 6-1 third choice.

Monba and Cowboy Cal ran 1-2 in the Blue Grass to give trainer Todd Pletcher a chance at ending his 0-for-19 record in the Derby.

Gayego, a 15-1 choice, raced exclusively on synthetic surfaces, but won the Arkansas Derby on the dirt in his last start.

Bob Black Jack, who starts from the No. 13 post, may be the only horse who can match the speed of Big Brown, having set a world record for six furlongs (1:06.53) in January. Others expected to contest the early lead are Cowboy Cal and Recapturetheglory.

“My horse’s pace, his maximum cruising speed is where I want to set him up at,” said Kent Desormeaux, Big Brown’s jockey. “I don’t know where it’s going to be. Big Brown will tell me where that is.”

Not known for his fashion sense, Dutrow planned to wear the same blue suit he donned for the Florida Derby, accented by a red tie.

“I told the Nordstrom’s guy I needed to look good Saturday,” he said.

In case there’s a trip to the winner’s circle.