Mets shortstop Francisco Lindor returns to the dugout after flying...

Mets shortstop Francisco Lindor returns to the dugout after flying out against the Athletics during the sixth inning of an MLB baseball game at Citi Field on Saturday. Credit: Kathleen Malone-Van Dyke

The Mets reached a season high in boos Saturday at Citi Field. The loudest were reserved for Kodai Senga, who teed up seven runs and recorded only seven outs, but he wasn’t alone in getting an earful — and deservedly so.

There were balls kicked around, bases uncovered (another mental gaffe by Francisco Lindor) and a bullpen blow-up, courtesy of the suddenly combustible Luke Weaver. The reeling reliever spoiled a brewing comeback by turning a one-run, eighth-inning deficit into an 11-6 rout by the A’s, the fourth straight loss by the Mets.

The day after president of baseball operations David Stearns put on rose-colored glasses for his monthly state-of-the-team address, he did mix in a few moments of clarity. “I’m not sure we’ve played our best baseball yet,” Stearns said.

Little did he realize how much worse the baseball could get Saturday, when Senga looked uninterested in throwing strikes, the offense sputtered again until the Mets already were in a 7-1 hole and Weaver ultimately torched the last flickers of momentum.

Bo Bichette, Francisco Alvarez and Jorge Polanco homered in trying to dig out of Senga’s mess, but the Mets still dropped to 7-8 because of sloppy play and subpar performance.

“We’re better than that, they know that,” manager Carlos Mendoza said. “They’ll be the first ones that will tell you. Making errors and mental mistakes — we’re better than that and we got to fix it.”

Put bluntly, it’s the kind of baseball that can get a manager fired in April, especially one in the last year of his contract who is put in charge of a $370 million payroll.

Something else that’s a particularly troubling sign for the Mets — and Mendoza’s future — is the puzzling behavior of Lindor, whose recurring mental screw-ups are very uncharacteristic of a veteran player once considered to be captain material for the Mets.

Earlier this month, in St. Louis, he forgot the number of outs in the first inning and also was picked off first base without even trying to get back. On Friday night, he got hung up at third base and gunned out to defuse a potential rally.

With one out in the second inning on Saturday, Lawrence Butler slapped what looked to be a double-play grounder to Marcus Semien, but Lindor didn’t break to cover second, instead ranging behind Semien on the edge of the outfield grass. As a result, Semien had to sprint over himself just to get one out and the A’s took a 2-1 lead on the mix-up.

“I went after the ball, and Marcus was there,” Lindor said. “Didn’t make it to second base and didn’t turn the double play. Senga could have got out of the inning right there and I didn’t help him.”

This is not the Lindor who has called Flushing home for the past five-plus seasons. He’s had his early offensive struggles and is having them again, hitting .167 (10-for-60) with zero homers, zero RBIs, 13 strikeouts and a .546 OPS. But we’ve never witnessed so many brain freezes from Lindor, and that’s the most baffling thing. He hasn’t provided much of an explanation, either.

“Not sure,” he said after a long pause. “Feel like I’m locked in. I feel like I’m in the game. Just happens. Got to be better.”

The Mets desperately need Lindor to be better, especially with Juan Soto not expected back until the end of this month because of a calf strain. Lindor is capable of carrying this team on his back, but the Mets can’t survive with him behaving like a zombie at pivotal moments.

Mendoza surely realizes this, which is why he had no problem addressing those questions after the game.

“It’s weird, because that’s not him,” he said. “It’s hard to explain.”

That was unusual candor from Mendoza about a star player, but it sounds as if he’s searching for reasons, just like the rest of us. On Soto bobblehead day, the manager insisted that Lindor’s recent mental blunders aren’t a product of any extra pressure with the $765 million slugger sidelined for a while.

“I don’t think so,” Mendoza said. “He’s the same guy. He shows up, he prepares, he works as hard as anybody. He wants to win. I don’t think it’s got anything to do with who’s in the lineup and who’s not. It’s weird.”

So Lindor is hearing boos again at Citi Field, and his mental state was even more worrisome Saturday than Senga’s dud.

This was supposed to be a bounce-back season for Senga, who came out of spring training poised to regain his long-lost ace status. But on Saturday, three starts in, he went full face-plant, giving up eight hits and seven runs in 2 1⁄3 innings and allowing a pair of long home runs. He was non-competitive and unable to throw the ball over the plate, as only 40 of his 72 pitches were strikes.

“At times like this, I think it’s really important as a starting pitcher to get the team off on the right foot,” Senga said through an interpreter. “However, I wasn’t able to do that today, so it’s very regretful.”

The Mets had plenty of regrets Saturday. As did the 38,244 fans who showed up and loudly voiced their disapproval.

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