NEW YORK -- Friday afternoon was a busy one for J.D. Martinez. There were places to be, people to meet, hands to shake. Upon arriving at Citi Field for the first time as a Met and changing into his new uniform, Martinez spoke to a staffer about his initial media briefing. He immediately hustled from there into a hitter’s meeting, then to the batting cage and finally to the field, where he hit one line drive so ferociously it caused a gaggle of stretching Cardinals players to scatter out of the way.

Martinez didn’t linger. More folks to meet after that. More handshakes. A little over a month after signing with the Mets, Martinez finally debuted for them in a 4-2 loss to the Cardinals.

“I made it,” he said.

From the time Spring Training ended, Martinez had toiled in Port St. Lucie, Fla., hoping to get his body and swing right. Now 36 years old, one of the more accomplished hitters of his generation didn’t want to rush. But as five early losses piled up for the Mets, Martinez began thinking to himself: “Try to hurry up. I want to be part of it. If they’re struggling, I want to struggle with them. If they’re doing good, I want to do good with them. It’s part of being a team.”

A back injury made that all but impossible for Martinez, who received a cortisone injection and sat for close to a week before continuing his ramp-up process. Finally, on Friday, Martinez made it back to the Majors. As he dug in for his first at-bat against his old college teammate Miles Mikolas, the center-field scoreboard listed his accolades.

“SIX-TIME ALL-STAR, THREE-TIME SILVER SLUGGER AWARD WINNER”

“315 HOME RUNS, 8TH AMONG ACTIVE PLAYERS”

These are the reasons the Mets signed Martinez -- not to save their offense, as co-hitting coach Jeremy Barnes put it, but to add to it. To make the lineup deeper. To make the hitters around him better.

That process began in the second inning, when Martinez redirected a Mikolas sinker to the opposite field for his first hit as a Met. Four innings later, Martinez came within a few feet of his first home run, banging an RBI double off the right-field fence. It was one of only two runs the Mets scored against Cardinals pitching, the other coming on a Tomás Nido homer.

The Cardinals fared slightly better, plating four runs off José Buttó on a pair of early home runs.

“Same hitter that I’ve seen over the years,” manager Carlos Mendoza said of Martinez. “This is a guy that’s always going to be tinkering with his swing. That’s how detail-oriented and how serious he takes his offense. I don’t think he’s ever going to tell you that he feels 100 percent, or he feels right. That’s who he is.”

That reputation is why the Mets felt comfortable inking Martinez to a $12 million contract despite his limitations. Martinez was never going to be ready for Opening Day. His history of physical ailments, like most players, has grown as he’s aged. Even now that he’s healthy and active, Martinez won’t start every day. (The Mets kept DJ Stewart on the roster for precisely this reason, to offer a DH alternative on nights when Martinez must rest.)

Despite all of that, the upside of Martinez is obvious, and should only grow as he settles into the rhythm of the season. Martinez joked that he’ll only remember about four percent of the names he learned on Friday. By the end of the weekend, that number should grow.

With each passing day, in fact, Martinez should become a bigger and bigger part of what the Mets are trying to do. He won’t be their everything, but he can unquestionably offer help.

“I’m not going to lie, writing that lineup and putting his name on the paper was a good feeling,” Mendoza said. “But at the same time, I don’t think it’s fair to put that pressure on him.”