"It's an awesome story," said Yankees pitcher Dellin Betances. "Nayyelyn is the true hero here. She was able to give her older brother the bone marrow to keep him living.
"This is what it's all about for us athletes to come here and spend the day with these two young heroes, and show them happiness and just have fun with them."
The Icla da Silva Foundation, which is the largest recruitment center for the Be the Match Registry in the United States, learned of Victor's disease and his search for a marrow donor. The foundation flew the Garcia family from the Dominican Republic, where they are from originally, to New York in August and paid for all the family's travel and medical expenses.
One month later, Victor and Nayyelyn underwent the transplant procedure after it was discovered they were perfect bone marrow matches. Siblings have the highest probability to be matches, though the odds for a match still aren't favorable.
"It's really nice," shortstop Didi Gregorius said. "I mean, you always want your older brother to be there for you, so it's something really great that she did."
Along with Betances and Gregorius were Starlin Castro and Aroldis Chapman, and the four players surprised the Garcia children at Yankee Stadium, where they believed they were getting a tour, before they rode together to the zoo.
After eating lunch under a pavilion at the flamingos exhibit, they all went to see the gorillas, which were as exciting for the players as they were for the children.
The players took photos of the gorillas, while Nayyelyn imitated them by thumping her chest. Victor looked on with amazement, as his dropped jaw hardly ever closed.
"It's always fun to give back," said Gregorius, who was making his first trip to the Bronx Zoo. "It's really fun walking around and talking to them. Standing here watching gorillas is really nice."
Victor is now in remission as he continues to recover from the procedure. Both he and Nayyelyn threw out the ceremonial first pitches at Monday night's game at Yankee Stadium.