Referee Mitch Dunning, center, is stretchered off the ice after an injury during the first period of an NHL hockey game between the Philadelphia Flyers and the Colorado Avalanche, Monday, Nov. 18, 2024, in Philadelphia. (AP Photo/Derik Hamilton)

Referee Mitch Dunning, bottom, lies on the ice after an injury during the first period of an NHL hockey game between the Philadelphia Flyers and the Colorado Avalanche, Monday, Nov. 18, 2024, in Philadelphia. (AP Photo/Derik Hamilton)

Colorado Avalanche's Josh Manson (42), right, talks to referee Mitch Dunning, center, as Dunning is stretchered off the ice after an injury during the first period of an NHL hockey game between the Philadelphia Flyers and the Avalanche, Monday, Nov. 18, 2024, in Philadelphia. (AP Photo/Derik Hamilton)

Referee Mitch Dunning, bottom left, lies on the ice after an injury during the first period of an NHL hockey game between the Philadelphia Flyers and the Colorado Avalanche, Monday, Nov. 18, 2024, in Philadelphia. (AP Photo/Derik Hamilton)