ATLANTA -- J.D. Martinez’s progression to the Majors has hit another snag. Martinez received a cortisone injection in his lower back Tuesday to treat tightness in the area. He will not swing a bat for three to five days while he recovers, which will push back his entire timeline.

Last spring with the Dodgers, Martinez dealt with a similar issue that also required cortisone to treat. He wound up missing 15 games.

“The way that he described it was last year he was swinging a bat within six days,” Mets manager Carlos Mendoza said. “So we’ll see how the next 48 to 72 hours he responds to the treatment, and then we’ll go from there. But as far as at-bats and things like that, he feels really good timing-wise, mechanics. So I’m not too concerned about this.”

The Mets signed Martinez, 36, a week before Opening Day in the hopes that he could help them sooner rather than later. Because Martinez had missed nearly all of Spring Training, he consented to a stint in the Minors to prepare his body for the rigors of an everyday DH role.

But Martinez was not ready to join New York when first eligible on Sunday. Initially, Mendoza cited “general body soreness” as the reason. The manager clarified on Tuesday that Martinez’s lower back is the issue.

“This is something that he’s dealt with the past few years, and he felt it again,” Mendoza said. “This guy’s almost to 80 at-bats in two weeks. I don’t think any position player when they first report to Spring Training goes through that quick of a ramp-up.”

Martinez played for Single-A St. Lucie last Friday and Saturday, and he was due to return to the lineup on Tuesday before his back issues intervened. He has not played -- and does not plan to play -- any outfield in the Minors.

While Mendoza was unwilling to put a timetable on Martinez’s progress, the slugger clearly is no longer an option for at least the first portion of the Mets’ upcoming homestand against the Royals and Pirates. Even if Martinez begins swinging a bat this weekend, he’ll still require a few days of practice, followed by additional Minor League games before the club will consider activating him. A best-case scenario probably involves Martinez joining the Mets for their next road trip through Los Angeles and San Francisco beginning April 19.

The Mets hope he will be worth the wait. A six-time All-Star, Martinez hit .271/.321/.572 with 33 home runs last season, despite back, hamstring and groin injuries limiting him to 113 games.

“In talking to him, he sounded pretty confident,” Mendoza said. “Like, 'Look, last year was a game-changer for me. I dealt with this in the past. There were times when I played through it, and it wasn’t a good feeling. Last year, I got this shot, and I was perfectly fine for the rest of the season. I don’t want to go up there now and have to deal with this the whole year. So why don’t we just get ahead of things and get it done with?' And that’s what we decided.”