Carlos Mendoza’s misplaced loyalty could be fatal Mets mistake

So much of this season, especially the last 4 ½ months, has been about fun, about characters, about an endless feel-good vibe that invaded the Mets clubhouse around June 1 and never let go. There were comebacks aplenty — both in the standings, and in the many games that allowed them to rise in those standings.

Fun is a big part of baseball. Fun has its place.

But this is no longer about positive vibes and cheerful mojo. There’s only so much that a purple fast-food mascot can do, especially when OMG has so swiftly turned to SMH. The Mets are now halfway to the abyss, and they face their latest must-win adventure Thursday night, Game 4 of the NLCS at Citi Field, after this 8-0 throttling in Game 3 .

Carlos Mendoza would surely prefer to channel Darrell Royal, the old Texas Longhorns coach, who famously said, “Dance with the one who brung ya.” In fact, less than 20 minutes after this slaughter was over, he literally paraphrased it.

“The guys out there got us to this point,” he said.

And look: part of why Mendoza had such a great rookie year as a manager is that he is unfailingly loyal. The players know he has their backs. He doesn’t make lineup switches out of panic. But this isn’t panic. The Mets can no longer afford to go with Royal’s credo, or Mendoza’s. Too much is at stake.

Mets vs. Dodgers live updates: Freddie Freeman out of lineup

The lineup for Game 4 should look different than the one he ran out for Game 3. But he said with absolute conviction that this will not happen. Francisco Alvarez is the obvious candidate to get a rest. His second-inning error led to the first two unearned runs and cast a pall over an electric crowd of 43,883 that desperately wanted to serve as the Mets’ wingman Wednesday.

He also struck out in the bottom of the inning with one out and the bases loaded, when even a sacrifice fly would have reengaged the ballpark. He has now left 10 runners on in the last two games. He’s young and he’s scuffling. Luis Torrens, his backup, is not Pudge Rodriguez and has only six hits since the first of August. But sometimes a day off is a necessary thing.

“He’s a good hitter, man, a good player,” Mendoza said of Alvarez. “He’ll come around.”

So no thought of going with Torrens?

“Alvy’s playing tomorrow,” he said. So that’s that.

Mets vs. Dodgers prediction: NLCS Game 4 odds, picks, bets for Thursday

And the J.D. Martinez/Jose Iglesias DH/second base combo, which sure seems to have reached the point of diminishing returns, will also return to Game 4. As with Alvarez, the Mets don’t exactly have Luis Arraez and Yordan Alvarez ready to replace them. But Jeff McNeil (assuming he’s healed enough to play defense) and Jesse Winker ought to be viable alternatives.

Except Mendoza already shut that down.

“We’re facing [Yoshinobu] Yamamoto,” Mendoza said. “Look at his reverse splits against right-handers.” And sure, that’s a fair point. There’s no obvious advantage to weighing a lineup against him with lefties.

This may sound like someone who’s a slave to analytics, but we’ve seen Mendoza’s work all year. It’s not that, not at all. If he displays a weakness for anything here, it’s a preponderance of trust. Martinez and Iglesias were fundamental to the Mets’ turnaround.

Martinez’s professionalism and leadership helped drag them from their springtime dregs. Iglesias’ energy opened a window and let in a gust of fresh air within minutes of his arrival in June. And he managed to keep it up the rest of the year.

CLICK HERE TO SIGN UP FOR OUR STARTING LINEUP NEWSLETTER

But Martinez hit .109 from Sept. 1 on, and he has zero extra-base hits in the postseason. Iglesias has started to regress to the mean in this series, flailing with men on base, and on defense he could have made a play on Alvarez’s wide throw in the second and didn’t, and his error very nearly opened the door to a Dodgers rally in Game 2.

Nobody is saying Alvarez, Martinez and Iglesias should be cast aside and smothered in mothballs. But the Mets have now been outscored 17-0 in their two losses in this series, and none of them were integral to their Game 2 win. It feels like a shake-up, even if just for one game, might be beneficial.

Mendoza disagrees. And his is the vote that counts.

“Someone’s going to step up and get the big hit for us,” Mendoza insisted, and that’s entirely on brand. He may not use the same rose-colored, Polyannaish words that Aaron Boone favors but a year with Mendy the manager has revealed that he’ll fight on behalf of his guys every bit as fiercely as Boone does, or anyone else.

It’s part of the reason the Mets are here. It is a good quality to have as a skipper. But so is this: knowing when to alter the chessboard. Joe Torre in 1996 famously benched Tino Martinez, Paul O’Neill and Wade Boggs in the World Series, three guys who’d absolutely driven him to the dance. We remember that because it worked.

And if Mendoza’s devotion to his guys bears out, we’ll remember that, too.

But it has to work.

For the latest in sports, top headlines, breaking news and more, visit nypost.com/sports/