The NHL didn't name anyone involved in the incident in a statement released Tuesday but the infraction went viral on social media after Twitter user Michael Ryan shared a clip. In the video, MacKinnon clearly slashes linesman Michael Cormier in the leg after losing a faceoff at centre ice during a game between the Avalanche and Boston Bruins.
According to Rule 40.3 in the NHL Rulebook, "any player who deliberately applies physical force to an official in any manner... which physical force is applied without intent to injury... shall be automatically suspended for not less than ten (10) games."
The NHL said that after investigating the incident and speaking with the officials involved it determined that "the player's intention was not to strike the official but, rather, to initiate contact with the opposing player. Given this conclusion, it has been determined that no further discipline is necessary."
A suspension for abuse of an official is rare in the NHL. The most famous recent example came in February 2016 when then-Flames defenceman Dennis Wideman shoved an official from behind, knocking him unsuspectingly to the ice. Wideman was suspended 20 games for the incident but, the suspension was later reduced to 10 games after an appeal.
"The safety of our on-ice officials is, and has always been, of paramount importance to us," the NHL's statement said Tuesday. "This decision should in no way be seen as a diminution of our steadfast concision to protect our officials."