This is the type of injury which would only happen to the Edmonton Oilers. Immediately after a draw, the official tripped over a stick and reached out to catch his balance. His hand found Nail Yakupov, yanking him down on the ice and landing on the forward’s leg/knee.
Watch as Yakupov’s leg folds under the linesman.
A slower look, via Reddit Hockey:
Yakupov had to be helped off the ice.
