The play in question occurred during Game 7 of Vegas' series against the Vancouver Canucks. In the final minutes of the second period, Reaves caught Motte with a high hit as the Canucks forward was coming out of the corner, his shoulder connecting with Motte's head.
In a video explaining the suspension, the NHL's Department of Player Safety said both elements of the Illegal Check to the Head rule were met on the play, with Motte's head being the main point of contact, and the NHL believing the play to be avoidable.
Game 1 between the Golden Knights and Stars is scheduled for Sunday at 8 p.m. ET. Reaves will be eligible to return to the lineup for Game 2 of the Conference Final series.