In the NHL, a young blue-liner's learning curve is steep and forbidding.

While forwards and goaltenders rely on natural instincts in their introductions to the league, defensemen often must make significant changes to adapt to the skill, speed, and strength at the highest level.

There are, of course, exceptions; players who make a seamless transition to the show with the same game that saw them dominate at previous levels.

Here are three players who represent the future of the blue line in the NHL.

Aaron Ekblad

It's almost impossible to fathom that Ekblad, mountainous and marvelous, is still in his teens. But that is the case for the 2014 first overall pick, who's returned to the Florida Panthers after a second All-Star appearance in as many NHL seasons.

As a rookie, Ekblad played in a top-pairing role with veteran Brian Campbell, learning the position on the fly from one of the game's most underrated defensemen. He quickly emerged as Florida's best player - in the eyes of goalie Roberto Luongo, at least - even if his mastery was largely outside the public eye.

Sixteen months later, on an upstart team leading the Atlantic Division, his dominance has come into clear focus. The Panthers' success is inextricably tied to Ekblad's presence, evidenced by his sizzling Goals For percentage (66) at even strength.

Oh, and the fact they haven't lost with Ekblad in the lineup in seven weeks.

Shayne Gostisbehere

Gostisbehere had to wait a little longer than Ekblad to make his mark, spending three seasons in Division I and then tearing his ACL in the American Hockey League just days after making his NHL debut.

But the South Floridian has burst onto the scene this season, albeit by different means, for the Philadelphia Flyers.

With eight goals and 22 points in 29 games, the D-man they call "Ghost" is producing points at a rate fractionally off the pace Erik Karlsson set last season en route to another Norris Trophy.

Gostisbehere ranks sixth in per-game scoring among defenseman, but his points are not cheap. His three overtime winners have him one shy of the league lead, and tied with 3-on-3 wizard Johnny Gaudreau and $80-million man Anze Kopitar.

Rasmus Ristolainen

Unlike Ekblad and Gostisbehere, Ristolainen took his lumps as a rookie. Unfairly tasked with anchoring a Buffalo Sabres blue line that was under constant attack in a throwaway season, he fashioned a woeful stat line.

The 21-year-old has emerged better for it, though, putting together a rock-solid sophomore season as a bona fide lead dog. Ristolainen's rates are all trending in the right direction under head coach Dan Bylsma, who trusts him with three minutes more than any other Sabres blue-liner.

Ristolainen's also discovered an attacking element in his game, and now ranks third on the team in scoring behind Ryan O'Reilly and Jack Eichel. His eight-goal, 31-point stat line was helped along by the first hat trick scored by a Sabres defenseman in 27 years.

He's still a work in progress, much like the Sabres, but Ristolainen appears primed to be the one who'll guide the team out of the muddy depths of the Eastern Conference.