MIAMI — The Mets traveled to Miami on Friday with three games to play and in full control of their own destiny.

That, it turns out, is the problem.

In an ugly game emblematic of an ugly season, the Mets disintegrated in ways all too common: sloppy defense, shoddy pitching and shabby situational hitting all contributed to a 6-2 loss to the Marlins at loanDepot park.

Now, destiny has turned into fate: With the Reds winning over the Brewers on Friday, the Mets have no definitive say on whether they’ll make the playoffs. The two teams are tied with two games to go and the Reds hold the tiebreaker, meaning the Mets could be eliminated as soon as Saturday.

By the manager’s own admission, it’s earned. The Mets are now 36-54 since their high-water mark of 21 games over .500 on June 13 — the fifth-worst record in that span.

“We put ourselves in this position,” Carlos Mendoza said. “Here we are. We’ve got to come back tomorrow and the next day now. . . . We did it to ourselves.”

Pete Alonso committed two miscues in a six-run sixth, Brandon Sproat cruised until getting nicked up that same inning, and the Mets went 1-for-10 with runners in scoring position. They didn’t record a hit after the third inning and stranded the bases loaded in the eighth.

Oh, and in case that wasn’t enough, they may have lost Brett Baty to a right oblique injury.

Baty said he felt it swinging through a pitch in the first inning and it really acted up after making a throw in the bottom of the frame. Mendoza said they’d know more Saturday, but it’s possible this could end the infielder’s season.

“It’s too early (to tell) but just watching the faces he was making and (and knowing) that area right there is tricky — we’ve got to wait until tomorrow to see what the severity is like,” he said.

Added Baty: “We’re going to see how it feels tomorrow. There are only two days left, so if there’s any possibility of me playing, I’m going to play.”

Much like this season, the game started well enough before imploding toward the middle.

The Mets scored both their runs in the first: Francisco Lindor drove Sandy Alcantara’s hanging sinker 392 feet to right-center for his 31st homer and his 11th leadoff home run of the year. Juan Soto singled and stole second and, with one out, Alonso lined a run-scoring double to the corner in left to put the Mets up by two. Soto also stole a base in the third, putting him two stolen bases shy of being just the seventh member of the 40-40 club.

That’ll be cold comfort during an idle October. And that became a very real possibility after the fifth.

Griffin Conine led off the inning with a single, Troy Johnston singled a ball off Alonso’s glove to put runners at the corners, and Heriberto Hernandez tripled into the corner in right to tie the game at 2. With one out, Jakob Marsee hit a grounder to first, but Alonso booted the ball; Jeff McNeil was able to grab the carom and throw the runner out at first, but the miscue allowed the go-ahead run to score.

“He was going on contact,” Alonso said. “It was a tough one but I’m still happy I was able to get an out in that situation. . . . So, not ideal. If I’d fielded it cleanly, I would have thrown it home.”

Sproat let up another single to Agustin Ramirez before getting lifted for Gregory Soto: He allowed four runs and five hits with a walk and two strikeouts over 4 2/3 innings.

Soto, meanwhile, failed to pay attention to Ramirez on the basepaths, allowing him to steal second, and Ramirez, seeing that Ronny Mauricio was far from the third-base bag, then took third easily — all of which allowed him to score on Edwards’ single. The disaster continued when Connor Norby obliterated a 2-and-1 sinker, hitting it 422 feet to left for his first career pinch-hit homer and the 6-2 Marlins lead.

The Mets looked utterly toothless after that. Alcantara settled down after the first, allowing two runs and six hits with two walks and three strikeouts over seven innings.

Mendoza credited Alcantara, but acknowledged early scoring followed by not much else has been an ongoing trend.

“Whenever you get chances, you’ve got to continue to punch and we haven’t been able to do that,” Mendoza said. “I think you’ve got to give (Alcantara) credit but yeah, it’s been going on for a while.”

The righty was lifted after giving up a leadoff walk to Lindor in the eighth. Soto hit into a forceout at second, and the Mets got two on after an error by Edwards at second base. Alonso’s bad day got worse, though, when Cade Gibson struck him out swinging. McNeil walked to load the bases and bring up the potential tying run in pinch hitter Mark Vientos, who popped out against Phillips.

“It’s on all of us,” Mendoza said. We continue to make those mistakes and it’s costing us games.”

Games they can no longer afford.

Notes & quotes. Clay Holmes will start Saturday . . . Tommy John surgery was recommended for Reed Garrett, but he’ll get a second opinion.

Laura Albanese

Laura Albanese is a reporter, feature writer and columnist covering local professional sports teams; she began at Newsday in 2007 as an intern.