One Met who won’t be gone by Monday’s trade deadline is Jorge Polanco, who continues to look lost at the plate.

He went 0-for-3 with a pair of strikeouts and a walk in a 2-0 loss to the Marlins on Sunday and was booed by the Citi Field crowd after his ninth-inning whiff.

Since his return July 7 from a lengthy stint on the injured list, no player with at least 50 plate appearances has been close to as unproductive as Polanco, who is 4-for-51 with a double, three walks and 18 strikeouts in his past 15 games.

“It’s fair to assume, with as much time as he missed, he’s still working back his timing and at the same time, getting to a base where he’s comfortable and confident with his hitting,’’ interim manager Andy Green said. “The results have not materialized.”

The Mets are left with little more than hoping that getting him away from Citi Field will do the trick.

“I’m excited to get him on the road,’’ Green said. “Honestly, just change the environment and maybe getting some early hitting in. We’ll see if we can jump-start him on the next road trip. It’s definitely been a tough stretch for him.”

Robert Stock will “be in the conversation” for another start in the Mets rotation, Green said after the right-hander limited the Marlins to one run in five innings in his first major league start since 2021.

Stock, 36, came back from thoracic outlet syndrome surgery during the spring and was emotional after his outing.

“It felt great,’’ the right-hander said. “To think about where I was a couple months ago, when I couldn’t lift my arm above my head, to be at Citi Field is as much of a dream come true as could be.”

Green managed Stock in the majors in San Diego earlier in their careers and called Stock’s solid 70-pitch performance “really impressive.”

MJ Melendez was designated for assignment to open a spot on the 40-man roster. The 27-year-old signed a one-year deal in the offseason and initially was expected to compete for an outfield spot.

He’s been supplanted by rookies Carson Benge and A.J. Ewing and had been with Triple-A Syracuse since late June.

In two-plus months on the major league roster, the lefty-swinging Melendez put up a .665 OPS in 144 plate appearances. He hit four homers.

The Mets needed to open two spots on the 40-man Sunday for right-hander Stock and righty Bryce Conley.

Right-hander Kevin Herget was also designated for assignment and Jonathan Pintaro was optioned to Syracuse.

The Mets claimed catcher Shawn Ross off waivers from the Pirates. The 26-year-old appeared in two games with Pittsburgh this season before being designated for assignment last week. He split most of the season between Double-A and Triple-A. Joey Gerver was designated for assignment to open a spot for Ross.