Kevin Kernan

Kevin Kernan

MLB

Steven Matz’s busy offseason: charity, grandpa Bert, country-singing girlfriend

PORT ST. LUCIE — More Steven Matz magic is just around the corner for the Mets.

The 6-foot-2 left-hander is healthy, determined and already in pre-camp, making the most of this massive opportunity as the Mets attempt to build the world’s greatest young starting rotation in 2016.

Here is what you need to know about Matz’s offseason, and this is straight out of how you would want your kid to act.

After going 4-0 with the Mets last season in six starts during an injury-harassed season and then showing up big in the postseason with three starts, one each in the NLDS, the NLCS and World Series, the kid from Stony Brook was busy.

First, he spent quality time with his family, including his grandfather Bert Moller, who became an Internet sensation because of his head-slapping while cheering on his grandson.

Soon after the World Series, Matz was at his grandfather’s home.

Steven Matz’s grandparents at his first game.Bill Kostroun

“Every year after the season, I always go over to his house and help him out with little odds and ends,’’ Matz told The Post on Tuesday. “Little things, like trimming some trees or he will tell me what to do and I’ll fix the sink or something. He guides me.’’

Then there was a charity excursion to Honduras, arranged by his agency, Icon Sports, and it was life-altering, Matz said.

“It’s a foundation called Hearts 2 Honduras,’’ Matz said.

A big part of the experience was visiting orphans, and Matz said the trip helped him in many ways.

“You know in baseball, you are always thinking about yourself,” he said. “God commands you to help others. You go down there and you wind up getting more out of it than you could imagine.’’

Like the story from one young man the foundation has helped. This young man’s life story began in the most difficult of ways.

“When he was just a few months old, he was left on the side of the road,’’ Matz explained.

The orphan grew up “and now he is going to college and he said he couldn’t have accomplished this without the help of the foundation,’’ Matz said. “It’s just amazing stuff.’’

Matz did some clinics for his high school coach, Lou Petrucci at Ward Melville.

“He’s a really good guy,’’ Matz said of Petrucci.

Matz also spent a month in Nashville.

Taylor CainGet Flex’d Photography

Why Nashville? His girlfriend, Taylor Cain, lives there and, like Matz, she is trying to make it as a star in another tough business — country music. And she is relying on the help of family as well — The Cains.

They are a most talented trio with unique harmonies. Taylor sings and plays guitar, and is joined by sister Madison and brother Logan.

“They are getting there,’’ Matz said of The Cains, noting their songs now pop up on SiriusXM Radio.

Mets minor league infielder T.J. Rivera and his wife went to Troy University with Taylor and introduced Matz to her.

The website Sounds Like Nashville just named The Cains’ song “Knock, Knock’’ as one of the 10 songs you should be listening to, and their cover of “Landslide’’ is popular on YouTube.

Matz arrived here on Monday and had been working out in the Tampa area the past few weeks. He must stay healthy this year after suffering some “weird’’ injuries last year that included a torn lat muscle, back stiffness and a blister. He’s working on holding runners better and is trying to master his pitches from the stretch as much as he does from the windup.

At 24, and still technically a rookie, there is much to learn.

“We all want to get back to the World Series, but you really have to take it one step at a time,’’ Matz said. “All the running, all the little stuff you have to do to make sure you stay healthy.

“My family is real excited for the season again. My grandma was a die-hard Mets fan. She watched every game. She passed away a while back, when I was like 13 or so. That was my grandfather’s wife, so for him to see what happened last year, was really special for him. It was really cool.’’

If he stays healthy, there will be much more Matz magic. Maybe he’ll even be in a country music video someday.