Matt Harvey of the Mets walks to the dugout against...

Matt Harvey of the Mets walks to the dugout against the Cubs at Citi Field on June 14, 2017. Credit: Jim McIsaac

Has there ever been a team that produces more collateral damage in victory than the Mets? It’s a rhetorical question. The answer is no.

Take Wednesday’s night’s come-from-behind, 9-4 win over the Cubs. Before the Mets even began to seriously climb back, they watched Matt Harvey shrink like a punctured balloon and Neil Walker collapse running to first base, his face twisted in agony, clutching behind his left leg.

This was sobering, painful, demoralizing stuff to watch unfold, for everyone at Citi Field. The fans, teammates, coaching staff. It’s impossible to have a feel-good win when two important members of the team end up shattered and could be lost for a significant period of time. That’s what we’re fully expecting, with both Harvey and Walker already booked for doctor’s visits Thursday.

Based on his reaction, Walker appears to have a hamstring injury, one severe enough that it potentially may cost him a minimum of one month, depending on the results of his scheduled MRI.

“I’m concerned,” is all manager Terry Collins could muster, and Walker wasn’t around after the game. As for Harvey, the sudden shutdown of his arm was even more alarming, and he didn’t even pretend to be optimistic. Harvey sounded defeated at his locker, repeatedly saying that he was “tired” and “fatigued.”

The best fastball he had all night, the 94-mph opening pitch, was hit onto the leftfield M&M deck by Anthony Rizzo. From there, it decelerated past 90, down to 87. Harvey said the last time he threw an 87-mph fastball was his freshman year in high school. The Cubs dented this shell of Harvey for three home runs, including Kyle Schwarber’s mammoth 467-foot blast over the Shea Bridge.

“My arm was not working at all,” Harvey said, his voice barely above a whisper.

Collins stayed with him for four innings, a total of 58 pitches, but even that was pushing Harvey too far. At one point, in the third inning, the manager saw 87 on the scoreboard, which labeled it a changeup. Collins turned to pitching coach Dan Warthen and asked if it was Harvey’s fastball. Both feared that it was. They got reliever Paul Sewald up, and gave Harvey one more inning.

“That was enough for me,” Collins said. “We don’t need any other issues here.”

Too late, Terry. The Mets are nothing but issues, patched together with Band-Aids and good intentions. We highly doubt it’s sustainable. But if the prognosis for Walker is a month or more, it should re-open the discussion about promoting Amed Rosario in the very near future.

Gavin Cecchini reportedly was scratched Wednesday at Triple-A Las Vegas, so he could be the immediate fill-in to buy more time. And a day earlier, when the Mets put Asdrubal Cabrera on the DL, they felt they could wait on Rosario, calling up the versatile T.J. Rivera instead. Now the Mets are short another infielder, and losing Walker could make them more desperate — not only to climb back into contention, but change the conversation among a restless fan base on the verge of packing it in for 2017. The Mets are getting to the point at which a leap of faith is going to be necessary.

Harvey’s troubling night only reinforces that. The Mets had just switched to a six-man rotation, only to see Harvey probably torpedo the plan. The way he spoke after Wednesday’s deflating performance, it would be tough to imagine him making his next start. Even if his arm eventually recharges, his confidence appears shot, and how do the Mets rebuild that?

“It’s been a very difficult year,” Harvey said. “An up-and-down season. But this is a pretty low point for me.”

When Harvey was removed, Steven Matz took his turn at the plate in the fourth inning, which made for another confounding moment. Not only was Yoenis Cespedes left out of the starting lineup for the third time in six games — after being pulled early in two that he did play in — Collins said that he wouldn’t be available to pinch hit until later in Wednesday’s game because the $110-million slugger doesn’t begin his warmup routine until the fifth inning.

Yeah, we don’t understand it, either. But these Mets defy convention, and somehow win despite the chaos.