After a miserable homestand, the Mets are shaking up their roster a bit.

Brett Baty’s prolonged struggles at the plate mean he’s getting company at third base.

Mark Vientos is getting called up from Triple-A Syracuse, The Post confirmed, and will meet the team in Philadelphia on Wednesday.

While Vientos is joining the Mets, it doesn’t mean the slumping Baty is going anywhere.

He’ll remain with the team, but because the lefty-swinging Baty has been especially poor against southpaws, the Mets are hoping to get some production from Vientos when they face lefties.

That starts Wednesday, when the Mets are scheduled to face lefty Ranger Suarez in Philadelphia. 

To make room for Vientos, Joey Wendle will be designated for assignment.

Wendle has played poorly since signing with the Mets in the offseason, including after the team chose to keep him instead of Zack Short, who was traded to the Red Sox late last month after also being DFA’d.

The move to shed themselves of Wendle — they have a week to trade or release him — leaves the Mets without a backup shortstop, though Jeff McNeil could play there in a pinch.

But that is far from their biggest issue, with a team that had trouble even getting a hit in two of its last four games.

Still, the fact Baty can’t find his way at the plate with any consistency leaves the Mets where they have been since last year at third base: without a clear-cut answer. 

Baty entered Tuesday hitless in his previous 11 at-bats and in a 1-for-19 rut over his previous six games.

Nothing changed in Tuesday’s 4-0 loss to the Phillies, as Baty was one of several Mets who were no match for Aaron Nola.

Baty’s recent numbers are especially ugly, with 15 strikeouts in his last 30 at-bats, a stretch in which he’s gone 3-for-30 with no extra-base hits since he had three hits — and a pair of homers — on May 3.

“He’s going through it, too,’’ Carlos Mendoza said of Baty prior to the game, as part of an explanation for why the struggling McNeil was out of the lineup and not Baty.

Mendoza said Baty was “in-between’’ during his at-bats.

“He’s being passive in counts and not swinging at pitches when he should be aggressive,’’ Mendoza said. “When he gets behind in counts, he’s chasing and not impacting the baseball the way he’s capable of.’’

Both the slumping Baty and McNeil were in the lineup against Philadelphia left-hander Cristopher Sanchez in Monday’s loss in Queens and the Mets clearly wanted to address that issue before Wednesday.

Baty has an OPS of just .476 facing lefties and hasn’t been good versus righties, either.

And over the last month, Baty is hitting just .176 with three extra-base hits.

“You’d like to have seen him make a bigger jump from last year,’’ one National League scout said. “They want to see what they have in him and there’s some improvement you can make out, especially at third, but he still has some stretches when you have to wonder how much better he can be.”

That leaves room for Vientos, who has shown flashes in the majors and was 3-for-7 with a homer in a brief three-game stint with the Mets last month when Starling Marte was on the bereavement list.

He didn’t do much in his latest stint at Triple-A, with mediocre numbers in his previous eight games — including just three extra-base hits, a .743 OPS and a dozen strikeouts in 35 plate appearances.

Still, the Mets need more offense, something that was proven again on Tuesday, when they didn’t get a base runner against Nola until the sixth inning — and that’s after they were nearly no-hit by the Braves on Saturday.

— Additional reporting by Mike Puma and Joel Sherman