An old plastic chair props open the back door of the gym. Inside, the glorious sounds of ... basketball.

A guard who once scored almost 2,000 high school points, holding the ball: “What’s coming next?”

A defender who once directed his college team to the NCAA Sweet 16: “I already know.”

“You think you know ...”

Nobody deferring to anyone.

“Too many rings to count,” someone said, watching some of the greatest ballplayers to walk through that back door at Neumann Goretti High, some of the greatest ever to play in the Philadelphia Catholic League.

They were together going fullcourt at 11th and Moore around dinner time last week because a couple of current Neumann Goretti assistant coaches, sitting around last summer, watched the summer hoop fest called The Basketball Tournament, featuring all sorts of college alumni teams, and got to thinking.

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“We stopped what we were doing, started writing down all the names,” said Neumann Goretti assistant Micah Coen about that conversation with Andrew Bowman. “Wow. We can put together a really serious team.”

So they have. The $1 million winner-take-all tournament to be shown on ESPN next month will include a first-ever high school alumni team, the NG Saints, from Neumann Goretti High, Philadelphia, Pennsylvania. (There’s another veteran TBT Philly entry too, Team Brotherly Love.)

Several generations are getting together inside that door to prepare. From Scoop Jardine and Rick Jackson and Jamal Wilson and D.J. Rivera to Tyreek Duren to Ja’Quan Newton and Troy Harper. Fresh Kimble and John Davis are expected to join up.

“I don’t think you can really have a scouting report for us,” Harper, the Drexel grad who played professionally in Germany this season, said just before the first full workout after the N-G team made the TBT field. “We have a lot of guards who can do everything.”

This group wasn’t sure they were going to have Duren since he’d committed to a La Salle alumni team first. But when the 64 teams were announced, and La Salle wasn’t selected, “My phone was ringing,” longtime Neumann Goretti coach Carl Arrigale said. “ ‘All right. I’m calling him right now.’ He picked up right away.”

» READ MORE: The bracket, with the NG Saints playing on July 17 in Wichita, Kan.

Arrigale isn’t coaching this team. He wants to simply enjoy it. Robert “Beattie” Taylor, another of his assistants who was on Arrigale’s first N-G team, is the right coach since he knows everyone out there. Tony Chennault, retired from the court, is kind of the general manager. He helped assemble the team, making calls.

“It’s great, seeing all the generations come together, how they all respect each other,” Arrigale said as the workout began.

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The intensity was medium level until something changed, just from one guy walking in the door, the workout already begun.

“Oh, it goes up 100 times,” Duren said later of that one player joining the fray. “You saw how much more competitive it got as soon as soon as he stepped on the court.”

Scoop Jardine was out of retirement. Jardine had put himself through a boot camp of sorts to get ready for this. Not all the way back, Jardine said later. He’s in life shape, not basketball shape just yet.

His trash talking began before he hit the court.

“You look real good,” Jardine told another former N-G star sitting on the bleachers. “Your skin’s all clear and ... ”

On the court, with the ball, next level.

“I’m the best point guard here,” Jardine announced, Duren covering him.

“Ten years ago,” Duren announced back.

Jardine drove and spun, and his layup attempt just fell off the rim. (Let’s note, Jardine’s former Syracuse teammate, Rick Jackson, might be the real key to the team, protecting the rim and cleaning up inside.)

When the workout ended, you saw the respect Duren and Jardine have for each other, trading tales about playing ball overseas, how those teams never seem to have the wireless ready in the apartments they’ve rented for American players.

“This is good, just to be around everyone,” Duren said.

“It’s home,” Jardine said. “I don’t mean that in a cliché way. I live a few blocks away. I grew up around the corner. Coming to Neumann, it was a safe haven for me. I’m sure it was for other guys, too.”

“Between the two of them, I think they can keep all these guys happy,” Arrigale said of Duren and Jardine at point guard.

If there’s anyone who can keep up with Jardine’s “beautiful” trash-talking, it might be Arrigale, telling Jamal Wilson, who averaged over 16 points a game as a senior at Rhode Island, that he’s never dived on the floor for a loose ball in his life, and how they could have beaten that Montrose Christian team featuring Kevin Durant a lot easier than they did if Wilson had made some shots. (You can find that game on YouTube.)

Wilson mimicked diving right off the court, into Arrigale’s legs.

“I always tell people, when Neumann comes to play, we’re going to make it ugly, but that makes us pretty.”

Scoop Jardine

“I’m very comfortable in here. It is home,” said Newton, who once broke the Philadelphia Catholic League scoring record out of this gym before going on to star at Miami. He did a G League stint this season, skipping overseas play for a season.

“I was just happy they reached out to me, to be honest,” said Harper, who showed his quick first step and a comfort zone from three-point range. “To play with guys I looked up to, and played with.”

Beyond the high-ability level, it was so obvious everyone on the court was a professional.

“The offense we’re going to run is real simple,” said Taylor, the coach. “Drive and kick stuff. Pick and pop. Quick movement.”

Nobody makes much of the fact that The Basketball Tournament made them a 16 seed. They just wanted in. They’ve played with mostly guards before, back to high school glory days. They’ve been favored, and they’ve sprung upsets. Nobody, they said, can bring more quality guards.

“No, no, nooo,” Taylor said, watching the generations play. “Our guards are just better than anyone’s.”

They’d been going for two hours … one more run. There was a negotiation even to that, how many points they’d play to. Playing tired is one thing, one guard said, you don’t want to play bad. They’d settled on playing to eight. You also needed to make a free throw for the last hoop to count.

“Our DNA is toughness,” Jardine said after the ball had stopped bouncing. “I always tell people, when Neumann comes to play, we’re going to make it ugly, but that makes us pretty.”