Eighteen-year-olds aren’t supposed to make the Edmonton Oilers anymore. That’s all in the past, isn’t it? Well, here’s something else that isn’t supposed to happen: Kailer Yamamoto, the first-rounder from 2017, isn’t supposed to be more NHL-ready than Jesse Puljujarvi, the first-rounder from 2016. Especially when Yamamoto stands five-foot-eight while Puljujarvi is six-foot-four, with a pro season in North America behind him. But isn’t that why they play the games? So long shots like Yamamoto can show all us experts that we may be wrong — again. “One of our best forwards again tonight,” assessed Oilers head coach Todd McLellan, after Yamamoto scored his fifth pre-season goal in a lopsided 6-2 rout by Carolina. Puljujarvi, chosen No. 4 overall in ’16, had opened the night on a line with Connor McDavid and Pat Maroon. But his game just isn’t there yet, full of looping circles and stick-reaching checks. He’s 203 pounds, but Yamamoto has knocked more players off of more pucks this pre-season at 155 pounds. By the second period, Yamamoto, picked 22nd in ’17, had taken his spot. Clearly, Yamamoto is well ahead of Puljujarvi at this early juncture in their careers. That may change one day, but it won’t change by the time McLellan and general manager Peter Chiarelli have to name their 23-man roster to start the season.