There was just 4:45 left in regulation, and the Penguins were clinging to a one-goal lead that would have sent them to Raleigh for the second round of the Stanley Cup playoffs.
Mika Zibanejad's late goal ultimately forced overtime, setting the stage for Artemi Panarin's eventual series-clinching overtime goal. The 4-3 loss in the extra frame ended the Penguins' season.
There's naturally some controversy on the sequence that led to Zibanejad's tying goal.
Just before the goal was scored, Marcus Pettersson was engaged in a battle with Alexis Lafreniere behind the net. Lafreniere put his arm around Pettersson's head and pulled his helmet off:
Players can't play without a helmet if their helmet comes off during play, so Pettersson was removed from the play, left the ice, and was replaced by Kris Letang. Meanwhile, John Marino lost the puck in the corner and turned it over to Zibanejad, who capitalized:
"A terrible rule ends up probably being the difference in the game," Sidney Crosby said.
When Tristan Jarry was asked what he saw on the tying goal, he used the moment to share his thoughts on the rule.
"I just saw Marcus skate off the ice," Jarry said. "I think that's a rule made by the NHL that could be changed. I don't think there's many injuries that happen when players play without helmets. I think it's something that's cost us. I think that he loses his helmet, he comes back to the net and he plays a guy out front, I think that's a nothing play."
Mike Sullivan made his thoughts on the rule clear:
"I think it stinks," Sullivan said. "He has to come off. His helmet get pulled off intentionally. But that's the rule."
According to the league rulebook, Pettersson didn't have to leave the ice. His other option was to just pick up the helmet and put it back on. Even if the chinstrap was undone, he would have been allowed to just stick the helmet back on his head and stay in the play. NHL Rule 9.6, first instituted in the 2019-20 season, reads as follows:
"A player on the ice whose helmet comes off during play shall be assessed a minor penalty if he does not exit the playing surface or retrieve and replace his helmet properly on his head (with or without his chin strap fastened), within a reasonable period of time. It is reasonable if a player who is making a play on the puck or who is in the vicinity of the puck and engaged in the play at the time his helmet comes off, takes the opportunity to complete the play before either exiting the ice or retrieving and replacing his helmet."
The dislodged helmet wasn't that far from Pettersson, and he could have spared a second or two toward that "reasonable period of time" by not throwing his arms up at the officials looking for the call.
The helmet rule is relatively new, and isn't something that comes up that frequently in games. So you can't expect every single player to know all of the intricacies surrounding the rule.
The thing is, though, that this sort of thing cost the Penguins a goal fairly recently in the playoffs. It was just a week shy of a full year ago, in Game 3 against the Islanders. It was the third period, and Marino's helmet was knocked off during a battle along the boards, and he picked it up and made a beeline to the bench with his bucket in hand:
What followed was Cal Clutterbuck's goal to bring the Islanders within one while the Penguins were essentially shorthanded. The Penguins held onto their lead that game and came away with the win:
The following day after practice, Sullivan said that the team had reached out to the NHL for clarity with the rule.
“We’re actually asking for a little more clarity on that circumstance because it’s our understanding that John can stay in the battle there,” Sullivan said. “We obviously get outnumbered because of it. We’re asking for clarity on that from the league. It’s my understanding that he can stay in that battle and look for the opportune time to get to the bench. That was just a circumstance that occurred in the game. Hopefully, we can avoid those moving forward. But part of it is just getting clarification from the league.”
Even if Pettersson and the Penguins did have a complete understanding of the rule and Pettersson just didn't think that he could have gotten the helmet on his head in a reasonable amount of time, that's not the only way the rule comes into question here.
The last part of Rule 9.6 says that "a player who intentionally removes an opponent’s helmet during play shall be assessed a minor penalty for roughing."
Whether Lafreniere had real intent in taking Pettersson's helmet off is up for debate. There's certainly a case to be made that a roughing penalty should have been assessed on the play.
It's a rule with a lot of gray area. That gray area ended up proving to be pretty costly on that goal, and perhaps the Penguins' season as a whole.