ATLANTA — The last time the Mets marched into Truist Park, they confronted this personal house of horrors and improbably punched their ticket into the playoffs in Game 161 of the 2024 season.

But the demons didn’t feel fully exorcized. Not when they returned Tuesday only to announce that Tylor Megill was headed to the 15-day injured list with a right elbow sprain — one in a lengthening and worrying list of hurt arms. It got no better in the eighth, when Atlanta rallied to tie the score, or in the ninth when a baserunning mix-up helped quash a rally of their own.

And then it somehow got even worse.

Huascar Brazoban loaded the bases with one out in the 10th to bring up Austin Riley, who hit a game-winning sacrifice fly to center as Atlanta came from behind to beat the Mets, 5-4.

Prior to that, the Mets had a chance to cut down the lead runner with men on first and second and no outs: Brazoban’s wild pitch had Luke Williams caught between second and third, but Francisco Alvarez made the reactionary decision to throw behind the runner to second, ensuring Williams pulled in safely at the corner. Brazoban then walked the next batter to load the bases for Riley.

“It feels bad,” Alvarez said. “The play is a reaction play and my reaction was to go to second base.”

The Mets losing streak extends to a season-high four games, as Atlanta scored three runs in the eighth off Reed Garrett to tie it.

David Peterson was dominating until the eighth when, with a 4-1 lead, he walked leadoff hitter Nick Allen and gave up a single to Ronald Acuna Jr. That ended his night in favor of Garrett, who allowed a single to pinch hitter Alex Verdugo to load the bases. Garrett got the next two outs, but Marcell Ozuna stroked a bases-clearing double to left to tie the score at 4.

Both Garrett and Alvarez took blame for that one: Garrett called fastball, but seeing that Ozuna had taken a bad hack at a splitter the pitch prior Alvarez changed the pitch.

“If it was executed a little down more, it would have been a ground ball,” Garrett said. “I could have still thrown the fastball if I wanted to . . . That’s kind of the ownership I need to take with calling my own pitches.”

Pete Alonso nearly pulled the Mets ahead in the ninth. Juan Soto singled and Alonso skied Dylan Lee’s fastball to deep right; Acuna, though, made a leaping catch at the wall and Soto, who was waiting for the umpire to say whether it had fallen in or not, was doubled off first.

“I feel like he just took way too long to make the decision,” Soto said. “He just put me in a tough spot.”

Coming off a complete-game shutout of the Nationals last week, Peterson allowed three runs and five hits with three walks and three strikeouts. And up until that eighth, the Mets had been cruising along with him.

Soto homered off Spencer Schwellenbach to put the Mets up 1-0 in the first, and Tyrone Taylor added a two-RBI double in the second. Matt Olson’s RBI single drew Atlanta to within 3-1 in the third before Taylor’s fifth-inning homer gave the Mets a three-run advantage.

That was all the good news the Mets would get, especially in light of the Megill injury.

Megill joins Kodai Senga, who went on the IL last week with a hamstring strain, along with Frankie Montas (lat) and Sean Manaea (oblique), who still haven’t made their 2025 debuts.

Though a sprain is a wrenching or tearing of the ligament, Megill said an MRI showed no structural damage to his UCL. There is, however, “lots of inflammation around the elbow — that’s kind of what’s [ticking] off the tendons and ligaments,” Megill said.

The plan is to shut Megill down for seven to 10 days and then re-evaluate, putting the best-case scenario for a return at four to five weeks, manager Carlos Mendoza said.

The team will use a spot starter Friday in Philadelphia, and Paul Blackburn will be slotted into the rotation until further notice.

Megill said he noticed something was off during his last start against the Rays.

“During the game, I just felt some pulling on my elbow, mainly on sliders, changeups . . . offspeed stuff,” he said. “That’s kind of why I had no idea where my sliders were going during the game. I hit two people. I spiked one 50 feet.”

Despite an MLB-best 2.98 ERA, the Mets are in a decidedly dicey predicament.

Montas, who’s slated to throw his final rehab appearance Wednesday, has pitched to a 13.17 ERA over five minor-league starts, and said last week that he was struggling with mechanical issues, including getting his arm slot right.

“Hopefully he gets through tomorrow with some good results, he bounces back and he’s part of the rotation,” Mendoza said. “…I watched his last bullpen at Citi Field and he felt really good, so [pitching coach Jeremy Hefner] continues to work with him. He liked what he saw mechanically from him even though the results weren’t there.”

The questions, though, don’t end there.

Manaea is slated to throw another rehab start with Triple-A Syracuse Friday but struggled in his third rehab start with High-A Brooklyn earlier this week, allowing four runs, five hits and two walks over 2 1/3 innings. The Mets are also in a stretch of 13 straight games.

“It’s part of it,” Mendoza said. “This is the first one and we’ve got a long ways to go. We’ve got to keep grinding.