PORT ST. LUCIE — Batters beware.

Mets pitchers are taking back the inner half of the plate under new pitching coach Dave Eiland with the blessing of new manager Mickey Callaway. They are going to pitch inside with a purpose, and sometimes they will miss in and hit batters.

That’s life in the major leagues.

If hitters are diving across the plate, there will be a toll to pay.

“Don’t let hitters get comfortable,’’ Eiland told The Post about the style of pitching he wants his Mets hurlers to have on the mound. “When you’re pitching, you have to be feared.”

Eiland then made his point crystal clear.

“There is one stat I hope we lead the league in, and that’s hit batters,’’ he said.

Consider yourself warned.

“Not because we are trying to hit guys, we’re not head-hunting,’’ Eiland said. “It’s because we are pitching them off the plate.

“And they’re diving,’’ Eiland added. “Is there anybody who doesn’t have body armor now? You see a lot of guys who are hitting good pitches that are down and away, that’s because they don’t have a fear of the ball in.

“I am not saying we are going to throw at people’s heads because we’re not. We are not going to throw behind them. We’re going to go in and when we go in, if we miss, we are going to miss in off the plate and we are going to hit some guys.

“That’s the way it goes.’’

Indeed.

Mets pitchers are locked into this new old-school philosophy. It fits their personalities, and as Noah Syndergaard told me of Eiland, with more than a glint of admiration in his eye, “Dave is a badass.”

So is Syndergaard.

“We have all these strengths, so you just add another tool to the toolbox,” Syndergaard said of the pitching-in strategy.

To make his point to the Mets pitchers, Eiland highlighted Syndergaard’s first World Series pitch in their meetings, when the two were on opposing sides.

“We talk about it all the time,” Eiland said of Syndergaard’s pitch.

Eiland was the Royals pitching coach in 2015. In Game 3, Syndergaard fired a 98-mph fastball up and in and over the head of Kansas City leadoff hitter Alcides Escobar, who wound up sitting on his backside in the dirt as fans went bonkers at Citi Field.

The next pitch was a breaking ball on the outer half. Syndergaard unleashed a 99-mph fastball past Escobar for the strikeout as the Mets went on to win, 9-3. It was their only victory in that World Series.

“Actually, after that first pitch I knew we were not going to win that game,” Eiland said. “The way we reacted to that. I leaned over to our bench coach and said, ‘Well, [Kelvin] Herrera, [Wade] Davis, [Luke] Hochevar and [Ryan] Madson won’t be pitching tonight because they got us on this one. We’re not winning this one.’’’

Eiland rested his “A’’ bullpen that night as the Royals went on to win the World Series in five games.

“Guys aren’t as comfortable when you pitch inside,” Jacob deGrom said. “It’s your plate. You want to own both sides of it. You’re away, away, away they get comfortable. Bring one in, it doesn’t even have to be that far off the plate and they are going to say, ‘Well, he’s going to come in here.’ It just puts that in their minds.’’

Message delivered. Pitch inside to achieve a strategy.

Mets hitters are backing their pitchers. Just listen to Todd Frazier.

“Syndergaard will come and get you, and I love that about him,” Frazier told The Post. “And guess what: What are you going to do? It is what it is. ‘I’m going to pick my guys up and if you got a problem with it, do something about it.’ He’s not afraid to go inside, which I love about him. Not for any intent. He’s not afraid to stare you down, either. Guess what: ‘I’m coming back in there.’ I want to play behind a guy like that.”

He will. Mets pitchers are pitching inside this year. Batters beware.