One down, one to go?
The thing about rookie of the year awards is they're one-shot deals. You really only get one chance at being a rookie - and while there may be good crops all around, only one of them will be recognized as having the best inaugural year of his class.
So it's a tight, one-off battle. And Auston Matthews will likely be in the conversation for the NHL's Calder Trophy throughout the 2016-17 season; that's just a thing first overall picks do. (Unless they're drafted by the Edmonton Oilers, that is.)
In preparation for his Calder bid, Matthews has already won a Rookie of the Year title.