NEW YORK -- Any thoughts of J.D. Martinez being a significant factor for the Mets in April have all but evaporated.

Martinez is “very unlikely” to join the Mets on their upcoming West Coast trip, according to manager Carlos Mendoza, as he continues to recover from a bout of lower back soreness. That trip runs through April 24, and president of baseball operations David Stearns said he believes Martinez could return “shortly thereafter.”

Even if that comes to pass, the Mets will play perhaps the entire first month of the season without Martinez, 36, who signed a $12 million guaranteed contract with about a week remaining in Spring Training.

Although Mets officials never expected Martinez to be ready for Opening Day given his compressed timeframe to train against live pitching, they were initially hopeful he could debut on or around April 7, when he was first eligible to return from an optional Minor League assignment.

But shortly after appearing in a pair of Minors games, Martinez reported enough lower back discomfort for the club to shut him down and administer a cortisone shot.

Martinez resumed swinging a bat this week, but he was initially limited to soft-toss drills and similar low-intensity work. It will take him at least another week-plus to ramp up to Major League game speed.

“It’s just where he’s at right now,” Mendoza said. “He’s got to go through full BP, face velo, face arms, before he goes back and plays a few games.”

Following their travel day back from the West Coast on April 25, the Mets will open a seven-game homestand against the Cardinals and Cubs.

“I think he just needs to get into a spot where he says, ‘I’m good to go. I feel good, and I’m ready,’” Stearns said.

Last April with the Dodgers, Martinez dealt with a similar issue, which also required cortisone to treat. He wound up missing 15 games, and the Mets are mirroring the Dodgers’ treatment plan based on Martinez’s feedback.

The veteran slugger only appeared in 113 games with Los Angeles due to back, hamstring and groin injuries. But he was productive when healthy, slashing .271/.321/.572 with 33 home runs.

As a free agent this offseason, Martinez stayed in shape, but he still required a ramp-up period to ready his body for the rigors of Major League games.

“Hopefully, that [will be] in the rear-view mirror,” Mendoza said. “But you never know. Hopefully, we caught it early, we were able to do what we needed to do. And hopefully, it’s something that he’ll play the whole year without any issues. But we’ll see. We’ll see how he responds.”