PORT ST. LUCIE – In the sweltering midday heat of Tradition Field, David Wright rounded third and headed for home. In more ways than one.

Wright, who has been away from the Mets for nearly four months as he suffers from spinal stenosis, fielded ground balls effortlessly and made strong throws, using his legs in his throwing motion more than he has in the past. He ran the bases hard, appearing to be a bit more mechanical in his form. And he hit line drives to all parts of Tradition Field, along with his batting practice partner Michael Cuddyer, during the nearly two-hour session.

Not getting the kind of carry they expected from such hard-hit balls, Wright and Cuddyer joked with minor league facilities director Paul Taglieri that the batting practice balls were “marshmallows.’’ Not those rock hard major league baseballs.

What caught my eye most though was how much fun Wright was having on the field, laughing and joking throughout.

At no point was there a hint of pain on his face. Only a smile.

Come Monday, Wright is expected to play in his first minor league rehab game for the St. Lucie Mets. This was the third day of a series of five straight workouts, and Wright came through with flying colors.

Games will offer moments of instant reaction, and that will be the true test.

Wright appeared to be a little more open in his batting stance with his knees bent more, lessening the pressure on his back. Between drills, Wright did stretching exercises and yoga-like movements to keep his back loose, working with Mets physical therapist John Zajac. It was a purposeful workout in every way.

When Wright finally came into the dugout to talk to two reporters, he was covered in sweat.

“That’s three days in a row now, I’m feeling good,’’ Wright said. “It’s quite a change. I knew it was going to be a long, slow process, but knock on wood, the way I felt a couple of months ago, it’s quite a drastic improvement.’’

Wright was feeling so good he even joked with manager Terry Collins, who stopped by on the way to St. Petersburg, that he wants to win Florida State League Player of the Week honors before moving on with his comeback.

There is no set timetable on how many minor league games Wright will play before he re-joins the Mets. He hasn’t played since April 14.

“Early in spring training I always feel overmatched,’’ the third baseman said. “Once I get past that feeling of being overmatched and start doing the things I know I am capable of, that’s when I know I am ready. I’m expecting a modified, shorter version. Once I feel dangerous at the plate, I’ll be good to go.

“Now it’s just a matter of continuing to maintain it to make sure I do all my stretching, my therapy work and my core exercises. I know there are going to be some ups and downs, especially when I start playing, but this is pretty encouraging.

“It’s not an injury, it’s a condition,’’ Wright explained. “It’s something I am going have to manage. With that being said, some days you wake up and you are going to feel good, and there are some days you wake up and you feel OK and with therapy and the stretching I do, I can get the needle moving more towards good. And some days, the doctor told me, it’s just going to be bad.’’

Those are the days he will ask out of the lineup.

“Terry understands that, and talking to guys like Don Mattingly and some of these other guys who have had it, they echo the exact same thing,’’ Wright said.

Yes, this is a new world of conditioning and exercise for Wright, but at 32, this is the way he will have to play the game he loves.

Wright plans to return to the Mets to impart valuable lessons about how to succeed down the stretch, stemming from the collapses of 2007 and 2008 in division races with the Phillies.

“Even I got caught up in it with Jimmy Rollins,’’ Wright told The Post. “Who cares what I say or what Jimmy says? You play each other 18 times, that is when you make your point, not on some radio show.

“I couldn’t be more proud of – especially the younger players – of what this team has done. It’s incredible. You sit on the bench and you can’t help but smile and see the success these guys are having and getting to do it on the national stage, where Jacob deGrom and Noah Syndergaard and [Daniel] Murphy are becoming household names because people are finally getting to see them play in meaningful games.

“Don’t get caught up in this nonsense that this team is the team to beat or that team is the team to beat. Just go out and play baseball, and when you take care of business, good things will happen.”

His teammates appear to be listening.

While the Nationals and Jayson Werth have proclaimed the NL East is theirs “to lose,’’ the first-place Mets keep grinding, having won six straight heading into Friday’s series at Tropicana Field against the Rays.

“We have two months left in the season and we have a chance to go out there and prove on the baseball field what we’ve been saying since spring training, and that’s what we need to not lose sight of – you don’t get any wins for going out there and talking,” Wright said.

“I hope our guys don’t get caught up in that — all it is is nonsense. Some teams get motivated by it. If the Nationals are motivated by that, hats off to them for trying to get their teammates fired up. We are a confident bunch, and I hope we just go out there and play the game right and play the game hard.’’

That is exactly what the Mets have been doing.

“We’re having fun,’’ Wright said. “It’s a different feeling when you add a guy like [Yoenis] Cespedes. He doesn’t say much, but you can tell he’s got that confidence. He expects to hit the ball hard every time, and that type of confidence can rub off on the younger players who have never been in this type of pennant race.’’

The Mets are in first place again. Wright, with his new stretching, core-based approach, can’t wait to join in all the fun.