DENVER -- Artturi Lehkonen is out weeks for the Colorado Avalanche with an upper-body injury.

The 28-year-old forward was injured after a collision with Seattle Kraken defenseman Jamie Oleksiak caused him to fall headfirst into the boards in the second period of a 4-3 loss at Ball Arena on Thursday.

Lehkonen was alert, responsive, and had full movement after the incident but had been taken to the hospital as a precaution. Avalanche coach Jared Bednar said following morning skate on Saturday that the injury isn't to Lehkonen's head.

"[He’s] not great. We're still gathering information, but he's going to miss weeks,” Bednar said. “Can't give you a timeline yet.

“I don't think it's a penalty (the hit by Oleksiak). I just think it's the ice that they're sort of making contact in there, and just the way he goes in, loses his footing and goes in headfirst.”

The Avalanche (8-5-0), who have five losses in their past seven games, were defeated 8-2 by the St. Louis Blues on Saturday.

Lehkonen is tied for fourth on the Avalanche with eight points (three goals, five assists) in 12 games and is averaging 18:30 of ice time per game. He has spent much of the season playing on the top line alongside Nathan MacKinnon and Mikko Rantanen.

Last season, Lehkonen finished third on the team with 21 goals and fifth with 51 points in 64 games.

"He's does everything. He's good on the power play, he's good on the penalty kill, he's a very versatile player and trustworthy and never really makes mistakes. So, it's going to be a big loss,” Rantanen said. “We got to find a way to get some wins without him, which is obviously not easy because he's a good player.”

When asked how he can replace Lehkonen in the lineup, Bednar said, “You don’t.”

Forward Andrew Cogliano, who has three assists in 11 games this season, will also miss the game against the Blues because of an upper-body injury.

“He's not going to go tonight either,” said Bednar. "Hopefully day to day.”