At 14:36 of the second period in the Bruins/Wild game, Minnesota requested a Coach's Challenge to review whether Boston was off-side prior to David Backes' goal.
After reviewing all available replays and consulting with the linesmen, NHL Hockey Operations staff determined that Boston's Ryan Spooner was off-side prior to the goal. According to Rule 78.7, "The standard for overturning the call in the event of a 'GOAL' call on the ice is that the Linesman, after reviewing any and all available replays and consulting with the Toronto Video Room, determines that one or more Players on the attacking team preceded the puck into the attacking zone prior to the goal being scored and that, as a result, the play should have been stopped for an "Off-side" infraction; where this standard is met, the goal will be disallowed."