Mets starting pitcher Matt Harvey shows emotion after getting out...

Mets starting pitcher Matt Harvey shows emotion after getting out of the fourth inning during Game 5 of the World Series against the Kansas City Royals at Citi Field on Sunday, Nov. 1, 2015. Credit: Jim McIsaac

PORT ST. LUCIE, Fla. — Matt Harvey has Bryce Harper’s back when it comes to defending the next generation’s more expressive group of young stars. So don’t expect Harvey to be targeting any body parts for the occasional bat flip or fist pump at the plate.

“You don’t want to create a circus,” Harvey said Friday morning. “But I don’t think that’s what he’s trying to accomplish. It’s just having fun. I think at no point whatsoever do you want to show up your opponent or show up the game. But having a little flair is never bad.”

Harper challenged some of baseball’s unwritten rules this week when he told ESPN the Magazine that baseball is a “tired sport, because you can’t express yourself. You can’t do what people in other sports do.” The reigning NL MVP went on to say that outbursts of emotion such as Jose Bautista’s bat flip last October should be celebrated rather than shunned.

Among the rising young stars Harper mentioned by name: Harvey and Jacob deGrom. The paradox, however, is that those two are on the receiving end of what Harper is talking about.

In the past, hitters took a fastball in the ribs for doing what Harper suggests. But Harvey, along with the rest of the Mets’ rotation, ultimately will be part of the group that polices this type of behavior. It’s the guy with the ball in his hand who will get to enforce whatever the new codes will look like. And Harvey suggests they may be more lenient toward on-field celebrations moving forward.

“I think, eventually, those kinds of changes will come about,” Harvey said. “We’re all kind of a similar age bracket. We’re all in our 20s. So it’s pretty fun to see what excitement we can bring to the game, and I think that’s what [Harper] was talking about. Trying to get more people involved, more fans involved. Create more excitement, whether it’s the things we do in uniform or fun things off the field. Just show a little more personality.”

Harvey, like Harper, has been at the forefront of baseball’s millennial movement. He’s got the colorful nickname (“Dark Knight”), is a regular on the New York social scene and isn’t shy about showing up on late-night talk shows. Expect that to continue, if not expand to other arenas that Harvey hasn’t explored yet.

“I think you still have to go about your business the right way and the way that works for you,” Harvey said. “But as far as doing fun things, like [Yoenis] Cespedes — he had a parade of cars come in, which was entertaining for us and entertaining for the fans. I think that’s what Bryce was trying to say.

“When [Harper] said baseball was tired, I think he might mean it’s boring for some people. He’s trying to get across that we want to do more interesting things, and in this day and age — with Instagram, Twitter and all that stuff — we’re more than just someone people acknowledge on the baseball field. His work ethic is second to none, and he obviously knows that’s the most important thing. But we do have other interests, and we’re a lot more than just baseball players.”

As for the time between the lines, Harvey knows he can be just as guilty as batters when it comes to a fist pump or loud scream to punctuate a huge strikeout. That’s going to happen, and he’s OK with those things happening on both sides.

“I’m a very traditional player,” Harvey said. “But when it’s deserving, I’m going to get excited. The way I’ve always played is to show no emotion, keep it straight. But when it’s unbearable to keep those emotions in, then obviously you let it out. You just don’t want to create a circus out there.”