Coach's Challenge: COL @ PIT - 15:56 of the First Period

At 15:56 of the first period in the Avalanche/Penguins game, Pittsburgh requested a Coach's Challenge to determine whether Colorado was off-side prior to Nathan MacKinnon's goal.
After reviewing all available replays and consulting with the Linesman, NHL Hockey Operations staff determined that Colorado's Erik Johnson 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 Toronto Video Room, after reviewing any and all available replays and consulting with the Linesman, 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."
Therefore the original call is overturned - no goal Colorado Avalanche.
The clock is re-set to show 4:08 (15:52 elapsed time), when the off-side infraction occurred.

Rule 78.7: Coach's Challenge
A team may only request a Coach's Challenge to review the following scenarios:
1. "Off-Side" Play Leading to a Goal
A play that results in a "GOAL" call on the ice where the defending team asserts that the play should have been stopped by reason of an "Off-side" infraction by the attacking team.
New for 2017-18: If the result of the challenge is that the play was "On-side", the goal shall count and the team that issued the challenge shall be assessed a minor penalty for delaying the game.
2. Scoring Plays Involving Potential "Interference on the Goalkeeper"
A play that results in a "GOAL" call on the ice where the defending team asserts that the goal should have been disallowed due to "Interference on the Goalkeeper," as described in Rules 69.1, 69.3 and 69.4; or
A play that results in a "NO GOAL" call on the ice despite the puck having entered the net, where the on-ice Officials have determined that the attacking team was guilty of "Interference on the Goalkeeper" but where the attacking team asserts: (i) there was no actual contact of any kind initiated by an attacking Player with the goalkeeper; or (ii) the attacking Player was pushed, shoved, or fouled by a defending Player causing the attacking Player to come into contact with the goalkeeper; or (iii) the attacking Player's positioning within the goal crease did not impair the goalkeeper's ability to defend his goal and, in fact, had no discernible impact on the play.
Updated for 2017-18: A team may only request a Coach's Challenge for Interference on the Goalkeeper if they have their time-out available and the Coach's Challenge must be effectively initiated prior to the resumption of play. If the Coach's Challenge does not result in the original call on the ice being overturned, the team exercising such challenge will forfeit its time-out. If the Coach's Challenge does result in the call on the ice being overturned, the team successfully exercising such challenge will retain its time-out.