But he's earned high marks so far.
"I think he's done a really good job," coach Claude Julien said. "I see a lot of David Pastrnak in him. A young player with so much talent and, basically, with time and experience and learning the little details of the game, he's only going to get better, so very, very similar situation."
Julien should know.
The now-Canadiens coach managed Pastrnak through the then-18-year-old's first foray into the NHL while he was coach of the Bruins in 2014-15. Pastrnak was the youngest player in the League, and Julien had to work to put him into situations that maximized his advantages and minimized his drawbacks as he started to blossom into the player he is now - a two-time 30-goal scorer who has 10 goals in his first 11 games this season.
Julien did that on Saturday by having center Phillip Danault take a heftier load, including some shifts in Kotkaniemi's spot. The idea was to protect Kotkaniemi from having to play against the Bruins' top line of Brad Marchand, Patrice Bergeron and Pastrnak.
"Especially on the road, you've got to try and protect those players, make sure you don't put them in situations where they're going to get exposed or lose their confidence," Julien said before the game.
For Kotkaniemi, that confidence is building. His mother recently moved to Montreal from Pori, Finland, to live with her son. It has eased the transition and, as he said, "I get good food every day, and it's nice to come home when she's there."
He has worked to adjust to the smaller ice, the pace and the strength of his opponents. He is seeing the fruits of his labors.
"From the time he started off in the rookie tournament, where he was really trying to find his way, he's made huge strides," Julien said.
There are still many more strides to be made.
It appears Kotkaniemi is on track to get there. He won't always have to be sheltered. He will get the assignments that his team shies away from now. He will be expected to do more and to be more, on the ice.
He will also be expected to score.