Terry Collins brought out the lineup card to home plate and chatted with the umpires. Dan Warthen walked in across the rightfield grass from the bullpen with the starting pitcher. These were two Mets scenes Wednesday night that could very well not be seen again at Citi Field.

Who will be the manager bringing out the lineup card on Opening Day here next year? Who will be guiding the pitching staff? And who will be on the roster? Jose Reyes started at second and Asdrubal Cabrera opened at third in this game against Atlanta, but will Reyes be re-signed and will Cabrera’s option be picked up?

Amid increasing talk that there will be a regime change in the dugout and with some on-field personnel decisions looming, the Mets gave an announced crowd of 28,617 one last in-person look.

The home finale was easy on the fans’ eyes. The Mets won, 7-1, behind Robert Gsellman’s six innings of one-run, six-hit work, Travis d’Arnaud’s tiebreaking two-run single in the fifth and Dominic Smith’s pinch-hit three-run homer in the seventh.

The season began with playoff expectations, but the Mets’ record is 69-90. They’re scheduled to finish their down season with three games at Philadelphia Friday through Sunday. Then there’s expected to be some interior redecorating.

The manager’s office has been at the center of the speculation after having the same tenant these last seven seasons.

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Although Collins’ contract is expiring, he says he isn’t retiring. But it has been reported that the Mets will probably replace the 68-year-old baseball lifer.

Collins sounded a little emotional beforehand when asked for his standout memories in this ballpark. He mentioned his first home game leading the team in 2011 and the fateful Game 5 of the World Series against Kansas City in 2015.

Yet the second-winningest manager in franchise history said there wouldn’t be a different feeling managing this last home game.

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“It’s going to feel real normal,” Collins said. “I’m down to six guys in the bullpen when I’ve got 11 bodies down there. It’s going to feel like it’s July.”

Warthen assumed his role in June of 2008. But there were reports Wednesday that the 64-year-old pitching coach likely won’t be asked back after a season overstocked with injuries and marked by underperformance as well. The Mets arrived with the majors’ third-worst ERA at 5.01.

“This guy puts his heart and soul in this job,” Collins said. “This has been a rough year when you look at your pitchers and they’ve come up with all varieties of injuries . . . But Dan has done a good job. He prepares them. Guys get better . . .

“You look at how Rafael Montero started the year and how he finished the year. Dan needs to get a little Pat on the back for that. In this market, everybody’s looking to blame somebody. Once in a while, somebody gets a pat. Dan Warthen has done a nice job with some of these young pitchers, getting them to pitch better.”

Gsellman hasn’t been one of his success stories, this start notwithstanding. The 24-year-old righthander has followed a promising 2016 with inconsistent results. He’s 8-7 with a 5.19 ERA.

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“It starts with his two-seam fastball,” Collins said. “That’s his bread-and-butter pitch . . . As he gets ready for spring training, he’s got to make sure he’s got the command of that, that it’s down in the zone, that it’s got the movement he would what.”

Notes & quotes: Righty relievers AJ Ramos and Erik Goeddel are day-to-day with biceps tendinitis . . . Lefthander Tommy Milone (elbow) was unavailable . . . The Mets finished 37-44 at home.