“I had a really good relationship with [Gardner] and we’re thinking about him,” a choked-up Mendoza said. “The whole Mets organization is thinking about the Gardner family.

“I got two boys, too, and they were pretty close.”

TAMPA — Aaron Boone said Sunday he was “heartbroken” for Brett Gardner and his family after the passing of their 14-year-old son.

Miller Gardner, the youngest son of the former Yankees outfielder, died on Friday after falling ill on a family vacation, Brett and Jessica Gardner said in a statement Sunday.

“We talk about being family all the time and even though Brett’s been gone for a few years, that doesn’t stop,” Boone said Sunday at Steinbrenner Field. “A lot of people in there [the clubhouse] that know that family intimately. It’s a very tough day and very tough news.”

Brett Gardner’s son, Miller, has died at the age of 14.

Brett Gardner (r.) and wife Jessica (second from l.) with sons Miller (second from r.) and Hunter (l.)

Brett and Jessica Gardner with their two sons in 2013.Getty Images

Boone said he had not yet spoken to Gardner, who was the Yankees’ de facto captain in the first four years of Boone’s tenure. But Boone, a father of four, got emotional on Sunday when talking about the Gardners’ loss.

“As best we can, we’ll be praying for the Gardner family and where we can, offering support,” Boone said. “That’s kind of the unimaginable that unfortunately that’s where we are with it. Very sad. Very tough.”

Mets manager Carlos Mendoza, who played with Gardner in the minor leagues in 2006 and ’07 before coaching him in the big leagues on Boone’s staff, also opened his postgame press conference Sunday by sending his thoughts and prayers to the Gardners.

Brett Gardner (l.) and Aaron Boone (r.)EPA

“I had a really good relationship with [Gardner] and we’re thinking about him,” a choked-up Mendoza said. “The whole Mets organization is thinking about the Gardner family.

“I got two boys, too, and they were pretty close.”