A win would make Napravnik the second woman to win a Triple Crown race, after Julie Krone won the Belmont aboard Colonial Affair in 1993. It would also be the first female jockey-filly pair to win a Triple Crown race.
"It's exciting," Napravnik said of the opportunity. "I think it's great to bring some attention to the sport."
Napravnik is already accomplishing one feat in Saturday's race, as her start will make her the only woman to ride in all three Triple Crown races in the same year. The 25-year-old rode Mylute to the best finishes by a female jockey in the first two legs of the Triple Crown, placing fifth in the Kentucky Derby and third in the Preakness.
Unlimited Budget can become the fourth filly to win the Belmont and the first since Rags to Riches — also trained by Pletcher — in 2007. The 3-year-old won the first four starts of her career before taking third in this year's Kentucky Oaks.
"I think this [is] one year where I think the fillies are as good as the boys," Unlimited Budget owner Mike Repole told Belmont officials Tuesday. "[Unlimited Budget] ran a good race when she was third in the Kentucky Oaks, and two fillies out of that race, Midnight Lucky and Close Hatches, came back to run 1-2 in the Acorn [Stakes]. Unlimited Budget is a large filly, and when the 15 horses come out, you'll think she's one of the colts. She also has a good mind for a mile and a half where she'll settle."
Repole made the Napravnik-Unlimited Budget pairing official Monday night after Mylute and Code West, the two horses Napravnik was previously scheduled to ride, pulled out of the 1 1/2-mile race.
Napravnik rode the filly in this year's Rachel Alexandra Stakes.
"She's a big, strong filly, and obviously she's been training well," Napravnik said. "With a big field, it's going to be a tough race for everyone. But I don't think [she will be intimidated] — she looks more like a colt. Plus, she can sit close to the pace, or close into it."
Though Pletcher doesn't have concerns about competing with the all-male field, the trainer has some worries about Unlimited Budget's pedigree, and the distance of the Belmont could be an issue for her down the stretch.
"In the Belmont, the key factor is getting the distance in the mile and a half," Pletcher said last week. "She's been successful at a mile and a sixteenth this year twice, and she was successful as a two-year-old going a mile and an eighth, so that's encouraging. … I'm a little bit concerned about the bottom side of her pedigree. She's a daughter of Street Sense and that certainly is encouraging, however, the bottom side of her pedigree maybe not as quite as deep in stamina as Rags to Riches was."
Pletcher also made history of his own with Monday's announcement — his five horses in the field are the most ever in the Belmont and account for a third of the current field.
Pletcher ran five horses in the Derby without success and skipped the Preakness altogether to prepare for the Belmont. In addition to Unlimited Budget, Pletcher has trained Overanalyze (11th in the Derby) and Midnight Taboo for Repole while starting Revolutionary (3rd) and Palace Malice (12th) for other owners.
Orb and Oxbow are looking to win two of the three jewels of the Triple Crown. Orb will be a favorite Saturday, but a Derby-Belmont double hasn't happened since 1985. Preakness winner Oxbow is hoping to pull the first Preakness-Belmont double since 2005.
Fifteen horses are currently committed to the race, and pole positions will be drawn Wednesday at 11 a.m.