MIAMI — Robert Gsellman, one of the few pitchers left standing for the Mets during this surreal season, struck the doomed pose with which too many before him could identify.

As the Marlins jogged off the field Tuesday night in the fourth inning, the Mets’ rally extinguished, Gsellman stood hunched over in agony beyond first base, his shaggy hair framing the pained expression on his face.

One by one, the fragile pieces of the Mets’ 2017 rotation have tumbled like so many blue-and-orange dominoes, from the final week of spring training to the waning days of June, and Gsellman incredibly became the sixth victim to fall, after only 54 pitches, in a 6-3 loss to the Marlins.

The Mets described Gsellman’s injury as a left hamstring strain, making him the second starter of this road trip to suffer a DL-worthy injury in the past nine days. Zack Wheeler was placed on the DL a week earlier with biceps tendinitis, Matt Harvey (scapula strain) is out for an undetermined period and Noah Syndergaard (lat strain) is anticipated back at some point in August, but hardly a guarantee to return. Jacob deGrom would be the only one of the seven starters from spring training to avoid the disabled list.

“It’s very frustrating,” Gsellman said. “We’re dropping like flies. I wanted to stay out there and compete. To give the team a chance to win.”

Unlike the others, who at least were sidelined with pitching-related injuries, Gsellman hurt himself running to first base, attempting to beat out a ground ball that nicked off the glove of Marlins starter Dan Straily.

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“It’s tough to comprehend,” Terry Collins said.

What else is there to say? The three-game sweep of the pitiful Giants at AT&T Park is now looking like a dead-cat bounce as some of the Mets’ most reliable players appear to be fading. After Travis d’Arnaud’s leadoff homer tied the score at 3 in the seventh, Jerry Blevins was unable to bail out Neil Ramirez when Ichiro Suzuki knifed the go-ahead single through the left side of the infield — a hole created when Wilmer Flores inexplicably broke toward third on the pitch. Otherwise, the ball may have been hit right to him.

“I just had a bad read,” Flores said. “That was it.”

Blevins, usually a late-inning savior, also surrendered a two-run single to Christian Yelich. As for Gsellman, he spoke optimistically about the strain, insisting that it wasn’t too serious. The pitcher expected to have an MRI Wednesday, but explained his dramatic reaction to the injury as more emotional than physical duress.

“It was definitely more frustration than pain,” Gsellman said.

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Gsellman had been on a steep dive lately, but after the Marlins took a 3-1 lead in the first inning, he retired seven of eight, striking out four. Finally, an uptick, something that seemed like a flicker of promise. But just as Gsellman appeared to turn a corner, or maybe self-correct, disaster struck. The Mets had rallied to within 3-2 in the fourth on Lucas Duda’s one-out double and d’Arnaud’s RBI single to centerfield, bringing up Gsellman with runners at first and second.

Gsellman poked the ball to the left of Straily, who hustled off the mound but was only able to redirect it with his glove into a slow roller toward second baseman Dee Gordon. It was then that Gsellman picked up his pace into a full-out sprint, but his stride suddenly changed to a hobble, his teeth clenched. That gave Gordon time he needed to essentially roll the baseball to first baseman Justin Bour, and the limping Gsellman arrived too late, even for an impossibly-slow developing play.

Earlier, the Marlins looked ready to end Gsellman’s night on their own. They ripped him for four hits, with Bour supplying a two-run single and Prado launching a two-out RBI-double. Gsellman was coming off a pair of ugly starts, when he allowed a total of 14 earned runs — including six homers — over 9 1/3 innings against the Nationals and Dodgers. Under normal circumstances, it was a disturbing trend the Mets couldn’t have continue. But they’ve exhausted nearly all of their options this season, in almost every department, so Gsellman’s job was safe regardless.

Unless he got hurt, of course.