Amazin’s waste gem by Walker

Taijuan Walker’s first season as a Met went from an All-Star nod to a second-half skid.

But he closed it out on a high note Wednesday night, even if the Mets didn’t hold up their end of the bargain.

Walker took a one-hit shutout into the eighth inning, only to leave with one out and two runners on, both of whom scored under Seth Lugo’s watch as the Marlins came back to beat the Mets 3-2 at Citi Field.

In his longest outing of the season, Walker gave up just two runs over 7 ¹/3 innings to finish with an ERA of 4.47. He walked off the mound, with a 2-0 lead, to a standing ovation.

It was a strong finishing touch for Walker. Before Wednesday, he had posted a 7.74 ERA in 12 starts since going to the All-Star Game.

“I know the numbers don’t look good, especially in the second half,” Walker said. “But to be where I was the last three years [throwing a combined 67 ¹/3 innings] and to go out there and make 29 starts, 30 games total and throw [159] innings, I would say that’s a win.”

After signing a two-year, $20 million just before spring training, Walker will be an important part of the Mets’ rotation in 2022.

Michael Conforto, who could be playing his final game as a Met at Citi Field on Thursday, crushed a 469-foot home run in the fourth inning to grab a 1-0 lead.

Noah Syndergaard will pitch a second outing on Friday or Saturday against the Braves, according to manager Luis Rojas, after making his long-awaited comeback from Tommy John surgery on Tuesday.

Team president Sandy Alderson said the club was “encouraged” by what it saw Tuesday — Syndergaard struck out two in a perfect inning, reaching 96 mph on his fastball, while not throwing breaking balls.

Catcher Tomas Nido landed on the IL with a left thumb sprain — his third stint with that injury this season. Patrick Mazeika was called up from Triple-A Syracuse to take his roster spot. … RHP Sean Reid-Foley was optioned to Triple-A Syracuse, making a roster spot for Syndergaard, who was the 29th man for Tuesday’s doubleheader.