NEWARK — This much hasn’t changed for Ryan Callahan: He is grinding his way through another postseason and has taken on a leadership role.

At 31, the battle-scarred right wing — who captained the Rangers for just shy of three seasons before being traded to Tampa Bay for Martin St. Louis in March 2014 — again is pushing the envelope when it counts.

After missing the final three games of the regular season with a lower-body injury, Callahan has played in all eight postseason games and has helped to set a tone for a team that dispatched the Red Wings in five and leads the Islanders two games to one in the second round.

“Once he got on our team, he instilled a lot of the work ethic, the grit that our team has,” Tyler Johnson said after practice Thursday. “He’s a guy you can rely on, a guy who you know is going to go 110 percent. In the handful of times I had played against him, I hated playing against him. He’s so competitive, he’s working so hard, a guy that slides headfirst to block a shot. It’s nuts to watch. And when someone has to speak up, he does.”

Callahan’s experience became more critical when captain Steven Stamkos underwent surgery to remove a blood clot near his right collarbone on April 2. Players say Callahan, who had only 10 goals this season, and fellow ex-Ranger Brian Boyle have stepped up to fill the gap in the locker room.

No longer the top-scoring forward he was in his 20s with the Rangers, for whom he put up 254 points in 450 games, Callahan primarily is a third-liner with Boyle, and both are key penalty-killers. But each had a goal in the 5-4 overtime win over the Islanders in Game 3, and Callahan has 30 hits and 12 blocked shots in the playoffs.

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Callahan helped recruit Boyle, who signed as a free agent three months after Callahan arrived.

“We built a pretty good friendship, and when I found out there was a chance that he might come here, I hopped on the phone right away to talk to him and give my pitch,” Callahan said Thursday.

Why? “His work ethic, the way he approached every game, willingness to do whatever.”

The Lightning’s Anton Stralman, underrated as a Rangers defenseman, currently is sidelined with a broken fibula. He signed with Tampa Bay shortly after Boyle.

“Those three guys have had a major impact on our team,” said coach Jon Cooper, who was hired in March 2013. Goalie Ben Bishop was acquired from the Senators a month later, he noted, “and then we needed guys who had been there before, guys who had been through those wars, the Callahans, the Boyles, the Stralmans, ones that had been to Stanley Cup Finals. We had such a young group coming up with the American League guys; who was gonna lead them?”

Among those who have stepped up is Callahan, who will play his 87th playoff game Friday night.

“You’ve got a 3-1 lead or it’s 2-2 going back home,” he said. “The series is a long way from over, but this is a big one.”