Ryan Callahan arrived in Tampa uneasy, unsure of his role with his new team and unfamiliar with the Lightning organization.

Callahan was part of a trade that saw two captains switch teams. Longtime Lightning fan favorite Martin St. Louis was shipped to the New York Rangers on March 4, 2014, for Callahan, who had been the Rangers captain for three seasons.

Callahan had never been traded before. The Rangers were the only team he knew, Callahan having spent all eight of his seasons in the NHL with the Blueshirts.

It didn’t take the newcomer long to assimilate to his new team.

After playing 24 regular season and playoff games with the Lightning to close out the 2013-14 season, Callahan was selected as an alternate captain for Opening Night of 2014-15, his first full season with the Bolts. Callahan was part of a rotating cast of nine players who wore the A on his Lightning sweater that season which saw the Bolts advance to the Stanley Cup Final. But Callahan was selected the most (62 of 82 regular season games), and, by the midpoint of the season, had been permanently installed as an alternate.

“Getting an A right away, it’s a privilege, that’s how I look at it,” Callahan said. “You have to take pride in that. It’s quite an honor to be able to wear a letter on your sweater, and it’s a responsibility I don’t take lightly. Not everybody gets to do it.”

Before the start of the current season, Lightning head coach Jon Cooper announced Callahan would be a permanent alternate for 2015-16 with the second A continuing to rotate. Callahan has been a captain or alternate captain in seven of his 10 seasons in the NHL.

“He leads out there with the way he plays, the way he works,” Bolts defenseman Anton Stralman said. “You can always count on him having a good effort out there on the ice. He never takes a day or a game off. He’s out there giving his all.”

On Friday, in the Bolts’ game against the Nashville Predators, Callahan will play in his 600th career NHL game. Callahan skated in 450 games with the Rangers prior to arriving in Tampa and will play in his 150th as a member of the Lightning when the Bolts battle the Preds.

“I feel like I just played game No. 100 not too long ago,” Callahan said. “It’s kind of scary. You don’t realize how fast it goes. I didn’t know that I’d ever get to 600.”

The 30-year-old Callahan is a heart and soul guy who leads by example on the ice and isn’t shy about speaking up in the locker room when needed. He paces the Lightning in the hustle categories: he has 126 hits this season, tops on the team by a wide margin (Stralman, at 81, is second), and he’s first among Bolts forwards for blocked shots (53).

“For somebody like Ryan to get to his 600th game, which is a lot of games in this league, the way he plays and for him to keep up at the high level he’s playing…how he sustains a level of play, of physicality, compete, hustle, all those things and with all the body contact and everything he does is pretty remarkable,” Cooper said.

Whether it’s game No. 1 or 600, Callahan only knows one way to play: all out.

“He’s one of those guys that you see on the ice and you just kind of want to follow them,” Stralman said. “The way he works is contagious.”