The incident occurred in a Feb. 23 game between Nipissing and UQTR. Linesman Nicolas Piche interrupted a fight by wrapping his arms around Cook and steering him towards the Nipissing bench.
When Piche prevented Cook from joining another scrum that had broken out, the defenceman punched Piche in the face and knocked him to the ice.
After reviewing the incident, the OUA banned Cook from participating in any competition sanctioned by the conference for the remainder of his university career.
Cook, 21, is in his first year at Nipissing following five seasons in the Ontario Hockey League with Erie and London.
He helped the Knights win the 2011-'12 OHL title.