Kotkaniemi, 20, was called for unsportsmanlike conduct midway through the second period for expressing his frustration toward the officials after Canucks netminder Braden Holtby tripped him with no penalty called. Vancouver scored on the ensuing man advantage to take a 3-2 lead.
"It was just a really dumb thing to do for a young guy," Kotkaniemi said, according to The Athletic's Arpon Basu. "That probably cost us a win, possibly cost us a win tonight. For sure we'll learn from that."
Head coach Claude Julien is hoping his young center can use Thursday's incident as a stepping stone in his development.
"There's no doubt that sometimes players get frustrated," Julien said. "He's a young player, and when you're a young player and you take on a ref - he hasn't earned his stripes yet in the NHL, if you will. He has to be more disciplined than that. That's certainly something he can learn, take a lesson from what happened today."
Kotkaniemi made up for his blunder by burying his first goal of the season to tie the back-and-forth affair with under 10 minutes to play in regulation. He also added an assist earlier in the game and posted a season-high Corsi For of 69.57%, according to Natural Stat Trick.