Once a young player transitions from junior or minor hockey into the NHL, his next challenge is proving that he has what it takes to make an impact at his sport's top level over the long term.
That's not always an easy task. Look at 2014 Calder Trophy winner Nathan MacKinnon, who slipped from 63 points and a plus-20 in his rookie season to 38 points and a minus-20 in his sophomore year.
Last season, we saw a fascinating mix of rookies grab their share of the spotlight—whether it was a can't-miss prospect like No.