"I think the hardest part is just the consistency … bringing it every single night," Duchene said. "That's something every young player struggles with a little bit at times. He played on, obviously, a really bad team this year with our team. He still shined through.
"There's nothing but great thing coming for him in his career."
Those great things could come as soon as next season, Duchene said.
"I mean, he's going to be an elite player for a long time in the League," Duchene said. "He's so big (6-foot-4, 211 pounds) and strong. He's got great hands, great speed and great vision. I think as he gets older he'll learn to use his size even better than he does already. He's just a horse of a kid already. He's going to be a great player for a long time."
Duchene isn't the only one expecting Rantanen to take another step. Avalanche defenseman Tyson Barrie saw Rantanen's evolution through a trying season up close.
"Mikko is a great kid and he's a great player," Barrie said. "He's such a big body. He's so smart with the puck. It was cool to see him kind of progress. It's scary the way he can hold onto the puck and makes everyone around him better.
"To me at least it looks like he's going to be a full-on superstar. That's a huge bright spot for us in Colorado. We're really looking forward to seeing that."
Rantanen is too.
"Of course I'll try to be a big piece for the team and try to help the team even more," he said. "But next year is next year. Of course I want to take on a bigger role on next year's team and be an even better player."