Bob and Sarah Zagaja have been training guide dogs for America's VetDogs in Smithtown and its sister organization, the Guide Dog Foundation, since 2011.

The Centerport couple have raised several pups and provided a home to two breeder dogs, but they've never had a dog more popular than "Buddy."

For the past year, they've cared for Buddy in their home and taken him to Citi Field, where he's treated like a celebrity.

"Everyone loves him here. The ushers, the security guards, the players. After the players, I'd say he's one of the biggest celebrities in the park," said Bob Zagaja.

"Buddy" is the newest guide dog sponsored by the Mets for their "Puppy With a Purpose" program.

The Zagaja's job is to provide him with his first steps of training on route to Buddy becoming a guide dog for a first responder or veteran in need.

Part of that training is done at Citi Field, where Buddy attends batting practice, meets fans and gets belly rubs from the coaches and players.

The couple also hand out "Buddy: The Mets Dog" trading cards to raise awareness about America's VetDogs and the "Puppy With a Purpose" program.

The Zagaja's say a trip around the stadium concourse provides learning opportunities for Buddy.

It teaches him to ignore crowds, to not get distracted by lights or noise and to not eat random scraps of food that fall from fans' plates.

"Popcorn is his kryptonite," said Sarah Zagaja. "We've been here when its so windy popcorn was blowing all around. That's his favorite thing."

But they know that time with Buddy is coming to an end. In a few weeks, they'll say goodbye to Buddy as he goes into formal training in Smithtown.

"It's difficult. I'm going to cry, Sarah is going to cry. It's not easy but it's why we do what we do and that's the ultimate goal," said Bob Zagaja.

But they'll see Buddy when he "graduates" and meets his new owner in September.