With every phone call the Mets field with a rotation-desperate hopeful trade partner, Justin Dunn gets closer to relevance. And to home.

The team’s No. 4 prospect, according to MLB.com, is making the case for a promotion, just a few months after he was promoted. The 22-year-old went from High-A St. Lucie to Double-A Binghamton in early June, a step closer to the majors and much closer to Freeport, where he grew up. And he’s pitching like he feels at home, carrying a 2.66 ERA in eight Eastern League starts, striking out 56 and walking 18 in 50 ²/₃ innings.

He is likely not destined for Queens this season, but he’s positioning himself as an option for next year. Dunn has heard the rumblings about the Mets breaking up their staff, even if he’d rather be ignorant to the possibility of a starting slot opening up.

“When you get to Double-A, you’re one call away,” Dunn said this weekend, before he held the Yankees’ Trenton affiliate to two runs (none earned) in six innings Saturday. “But at the same time, you gotta push that to the back burner and go about your work out there. I try not to think about that at all.

“You have no control over whether you go up or down. When they decide you’re ready, you’re ready. You’re waiting on the call. … I just go out and try to pitch and put up zeroes.”

That’s what he’s done. With a fastball that hums in the low-to-mid 90s but touches 96 and multiple breaking pitches that Binghamton manager Luis Rojas praised, the right-handed Dunn has been a standout in a system that doesn’t have many. Of the Mets’ top rotation prospects, including David Peterson, Anthony Kay and the rehabbing Jordan Humphreys and Thomas Szapucki, Dunn is the closest to being ready.

“His changeup needs to sharpen up,” Rojas said about the 19th-overall pick in 2016. “He needs to be more consistent with his fastball at the bottom of the zone. He needs to know when to use his fastball to play up more. … Once he becomes more consistent doing that, I know he’s going to keep moving up in the ladder, and he’ll be a big-league pitcher one day.”

The rise of Dunn looked distant last year, when he struggled with Single-A competition, the Mets at various points shutting him down and bringing him out of the bullpen to try to spark him. Dunn, who comes across as more a grizzled, thoughtful veteran than a kid two years removed from Boston College, blames his lost year on being too far inside his head.

This season, he’s put in significant time with multiple mental-skills coaches and feels more at peace with his brain and body.

“This year I can make corrections on the fly,” Dunn said. “If I feel something like I pulled off a pitch too early, I can key it, say, ‘All right, I pulled off, that’s why the pitch did that.’ My sense of feel is heightened.”

“How he handles himself,” Rojas said about what stands out about Dunn. “He’s out there, he slows things down. He looks like a mature pitcher even though he just got here.”

The closer Dunn gets to Citi Field, the closer he gets to his family. When he was in Florida and pitching to a 5.00 ERA last year, he had nowhere to turn. Now he can look to the stands and see his mother, father and little brother, having taken a three-hour ride to Binghamton to provide emotional support.

Of course, he doesn’t need to look to know they’re there.

“I don’t really hear much when I’m on the mound, but there’s one distinctive voice I hear, it’s my mother’s.”

She’s not shy.

“Lots of times it’s, ‘Breathe, breathe, breathe, on the mound, buddy,’ ” he said about her shouting. “ ‘Control your breathing, trust your stuff, you got this.’ She sometimes knows my body better than I do — she’ll say, ‘Stay back, you pulled off.’ I can always hear it.”

With every start and with the possibility that the Mets’ rotation gets hit by the upcoming sell-off, Dunn gets closer to making noise of his own.