NEW YORK (AP) – There’s no Triple Crown on the line and the Kentucky Derby winner isn’t running, yet there’s still a compelling story line for Saturday’s Belmont Stakes – a filly is in the field.

Rags to Riches takes on Preakness winner Curlin and the rest of the boys in her attempt to become the third filly to win the final jewel of the Triple Crown.

Curlin may be the betting favorite, but Rags to Riches will surely be the sentimental choice among many at Belmont Park.

“I’m very curious to see how she stacks up against what I think is a group of excellent 3-year-olds,” Curlin’s trainer Steve Asmussen said.

Rags to Riches, who ran her winning streak to four in a row by taking the Kentucky Oaks by 4 1/4 lengths five weeks ago, jazzes up a Belmont that will be without Derby winner Street Sense. Trainer Carl Nafzger declared his colt out of the race after his Triple Crown bid ended in the Preakness.

“It’s a talented field, all the right horses are here except for Street Sense,” said Hall of Fame trainer Nick Zito, who will send out long shot C P West, fourth in the Preakness. “We’re giving it a shot.”

At 1 1/2 miles, the Belmont is the longest and most grueling of the Triple Crown races, but of course, most of the trainers believe their horses fit the course.

Todd Pletcher, who trains Rags to Riches, may have the strongest case. His filly is a daughter of 1992 Belmont winner A.P. Indy and a half sister to last year’s Belmont winner, Jazil. And with her powerful running style, it all added up to taking a shot at history.

“At the end of the day, we’re in this business to try and do something special on Saturday,” said Mr. Pletcher, who is 0-for-28 in Triple Crown races. “This hasn’t been done in modern times.”

Ruthless won the inaugural Belmont in 1867 and Tanya was the other winner, in 1905. Winning Colors, who won the Derby in 1988, was the last filly to win a Triple Crown race.

“I do think going a mile and a half is an advantage for her, and she’s also fresh,” said jockey John Velazquez, who will be aboard the filly for the first time.

The way Curlin came back from his Derby loss to edge Street Sense by a head in the Preakness, though, the imposing chestnut colt may be too good for all six of his rivals.

“It’s so tough for someone who hadn’t felt defeat to rebound off of it,” Mr. Asmussen said. “And he rebounded emphatically.”

So has Mr. Asmussen.

The trainer who set a record with 555 victories in 2004, was suspended for six months last year after one of his horses tested positive for a local anesthetic following a race at Evangeline Downs in Louisiana. Even though he wasn’t at the track at the time, he took responsibility. “I think everybody knew how brilliant he was before the Derby,” Mr. Asmussen said. “His attitude off losing the Derby was very determined, somewhat aggressive. He’s definitely a competitor.”

Mr. Asmussen believes Rags to Riches brings a certain amount of curiosity to the race, but his biggest concern is Hard Spun, the Derby runner-up and third-place finisher in the Preakness.

“He’s one of only two horses that beat Curlin, and that has to be acknowledged,” he said. “I think he’s a quality horse.”

Hard Spun was three lengths ahead in the 1 1/4-mile Derby with a quarter-mile to go and in front with a half-mile to go in the 1 3-16th-mile Preakness. Trainer Larry Jones is hoping for a different result, and believes it can happen with a slower pace.

“Different distance, different pace scenario,” Mr. Jones said. “We can’t keep going out there the way we’ve been going.”

To that end, Hard Spun will have a new rider in Garrett Gomez, who replaces Mario Pino.

“I hated to change, but felt like we needed to do something,” Jones said, noting that Gomez is more familiar with the wide, sweeping turns of Belmont.

Look for Hard Spun and Slew’s Tizzy to move to the front early, with Curlin, Rags to Riches and C P West just behind the leaders. Late-closing long shots Tiago and Imawildandcrazyguy will gallop along at the rear of the pack and hope the others tire as they gain momentum for a stretch run.

That’s when the field enters unknown territory, a final quarter-mile that has been the undoing of many Triple Crown attempts, most recently in 2004, when Derby and Preakness winner Smarty Jones was run down by Birdstone.

“A quarter-mile added on to the Kentucky Derby (distance) seems extreme,” Asmussen said. “That’s what makes the Belmont such a special race.”