Drew Smith made his return to the bullpen Monday after serving a 10-game suspension for violating MLB’s ban on sticky substances and didn’t have the impact he wanted to.

Smith came in to start the sixth with the Mets up by a run and was one strike away from completing a scoreless inning when he allowed a 422-foot, two-run homer to Joey Wiemer that proved to be the game-winner.

“I felt completely normal,” said Smith, who insisted he had only used rosin when he was tossed before throwing a pitch against the Yankees on June 13. “Physically, I felt really good.”

He was checked for sticky substances on his way to the mound, which Smith said, “cleared my head.”

But then he left a 2-2 four-seam fastball to Wiemer over the heart of the plate and Wiemer hammered it to center.

The blow came a day after an eighth-inning bullpen implosion cost the Mets a game in Philadelphia.

Prior to Monday’s loss, veteran left-hander T.J. McFarland’s contract was purchased from Triple-A Syracuse, with Josh Walker optioned to Syracuse.

Walker, also a lefty, gave up three straight base runners on Sunday and they all scored when Jeff Brigham also struggled and David Robertson wasn’t used.

The Mets hope McFarland fares better.

The 34-year-old signed a minor league deal with the Mets in the offseason after a rough final season with the Cardinals in 2022. McFarland had a WHIP of 1.622 in 32 ²/₃ innings with St. Louis, but pitched well in 2021 with the Cardinals.

In 23 games with Syracuse, McFarland had an unimpressive WHIP of 1.439, but was coming off his best outing of the season when he tossed two scoreless innings, striking out five.

The Mets would like to ease the stress placed on the only other lefty in the pen, Brooks Raley, and they were caught shorthanded in Sunday’s loss to the Phillies.

Buck Showalter opted to stay away from more reliable arms like Adam Ottavino and Raley and instead went with Brigham and Walker, to brutal results.

David Peterson will start Tuesday against Milwaukee in his first major league start since he was sent to Syracuse in May after five straight ugly starts.

Joey Lucchesi had been pitching better — seemingly — at Syracuse, but Showalter said pitching coach Jeremy Hefner and the front office agreed Peterson was the right choice.

The 27-year-old first-round pick pitched poorly during his first stint in the rotation this season, with an 8.08 ERA.

Peterson showed considerable promise in 2022, with a 3.83 ERA in 28 appearances — and 19 starts — last year with the Mets.

Peterson will take Tylor Megill’s spot in the rotation after Megill couldn’t stick in the rotation, as both pitchers have struggled with command.

Peterson was walloped for 12.5 hits per nine innings this season, while Megill was also hit hard and saw his walk rate nearly double from 2022.

Justin Verlander was hit with a pitch clock violation to start the third inning, when it was ruled that he threw a warm-up pitch too close to the start of the inning.

Right-hander Mike Vasil was named to the National League Futures Game roster on Monday.

The 23-year-old Vasil has made two starts at Syracuse since being promoted from Double-A Binghamton.

He’s considered the organization’s No. 8 prospect by MLB Pipeline.

The Futures Game will be played July 8 at T-Mobile Park in Seattle.

The Mets might have had other representatives at the game, but other prospects like Brett Baty and Francisco Alvarez are in Queens.

Ronny Mauricio did not get selected.

The Mets will have a non-alcoholic pop-up at Citi Field from June 29-July 2 for fans 21 and older.

The pop-up, Absence of Proof, will feature alcohol-free mocktails and is being presented by Cadillac and Dunkin Donuts.