He could be but he doesn't have a history of being well over his peer group prior to last season.
It's easy for me to bet against a young player matching an exceptional rookie performance because it's even rarer that players can sustain, much less improve in situations similar to Gostisbehere.
Yeah...Ghost just came out of nowhere....unless you watch lots of hockey:
Award Year
All-ECAC Hockey Rookie Team 2011–12
ECAC Hockey All-Tournament Team 2012
WJC United States Gold 2013
All-ECAC Hockey Second Team 2012–13
AHCA East Second-Team All-American 2012–13
All-ECAC Hockey First Team 2013–14
AHCA East First-Team All-American 2013–14
NCAA Division I Men's Ice Hockey Championship 2014
NCAA All-Tournament Team 2014
ECAC Hockey All-Tournament Team 2014
ECAC Hockey Best Defensive Defenseman 2014
NCAA All-Tournament Team 2014
NCAA Frozen Four Most Outstanding Player 2014
Barry Ashbee Trophy 2015–16
Gene Hart Memorial Award 2015–16
NHL All Rookie Team 2015-16
NHL Calder Trophy Runner Up 2015-16
On February 13, 2016, he broke Barry Beck's point streak record for a rookie defenseman with a goal against the New Jersey Devils, extending his streak to 11 games.
On February 20, 2016, he extended his point streak to 15 games with an overtime goal against Toronto. Gostisbehere became the first rookie in NHL history to record 4 OT goals in a season.
It sort of looks like Ghost has been good for awhile.