Things can change quickly in this game, and the Penguins were reminded of that Saturday night.
One moment, defenseman Kris Letang was in the Montreal zone, trying to get off a shot that would break a 3-3 tie at the Bell Centre late in the third period.
The next, Letang was on the ice, bleeding heavily from his nose which had just been broken by a hit from Max Pacioretty of the Canadiens.
Letang was escorted to the locker room, had his nose realigned, received medical confirmation that he hadn't sustained a concussion and was back on the ice for the start of overtime.
And 129 seconds later, he ended the game by tossing a puck past Montreal goalie Carey Price.
Letang, then, got some revenge for the head shot he absorbed from Pacioretty, and Pacioretty -- who was not penalized for the hit -- should learn today if he'll be getting some unscheduled time off. He has a phone hearing scheduled with Brendan Shanahan, who handles supplemental discipline for the league.
Early indications were that Letang came through the incident with nothing more serious that his fractured nose, although it's worth noting that Sidney Crosby said he didn't experience any concussion symptoms until several days after then-Washington center David Steckel had laid him out with a blindside blow to the head Jan. 1.
But even if Letang's injury doesn't prove to be one of the lost-time variety -- his absence Saturday lasted just over three minutes -- it easily could have been.
And that would have put the Penguins back in the all-too-familiar position of being without one of their core players, which has been the case most of the time since the start of the 2010-11 season.
Oh, their lineup was intact for a few days in early January, when Jordan Staal returned after missing 39 games because of a foot injury and its complications and Crosby had yet to be diagnosed with his concussion, but that was the only time it happened until the past week.
Assuming that Letang is able to dress when the Penguins visit the New York Rangers at 7:38 p.m. Tuesday -- and that none of his high-profile teammates has an undisclosed injury that would force him to sit out -- it will mark the fifth consecutive game the Penguins have been able to dress something awfully close to their lineup of choice.
Coach Dan Bylsma and his staff likely would try to find a spot for forward Dustin Jeffrey or defenseman Ben Lovejoy if they weren't on injured reserve, but both are complementary players on this team, and it's rare for any club to be injury-free at this point of the season.
For one of the few times in more than a year, however, the Penguins aren't missing one or more of the players who form the foundation of their team.
They are 3-1 in the four games since Crosby and defenseman Zbynek Michalek returned to the lineup against the New York Islanders last Monday and have, at times, been even more impressive on the ice than they are on paper.
"This is the first time in a couple of years that everybody's in and playing to their full potential," winger Pascal Dupuis said. "Everybody's in, and it's fun to play."
The impact of having the lineup intact has been most obvious in the offensive zone, and a lot of that has to do with Crosby. He has scored or assisted on eight of the 17 goals the Penguins have manufactured the past four games.
Since Crosby resumed playing, Bylsma has deployed some imposing groups of forwards -- including units featuring Crosby with Malkin, Malkin with Staal, and Crosby, Malkin and Staal together -- that give opponents little opportunity to recover from one offensive assault before the next one forms.
"The team comes in waves," winger James Neal said. "It's one line after another. With all the great players, you can put any combination together. It's a fun hockey team."
As the Letang-Pacioretty incident illustrates, the Penguins' run of good health for the players who make up their nucleus could end at any time, and it wouldn't necessarily require a nasty hit to someone's head to make that happen.
All it takes is for a guy to catch his skate in a rut. For one to fall awkwardly into the boards. For one to be struck by a shot that hits a half-inch away from a protected area.
But for now, the Penguins are healthy, and playing with the confidence of a group that grasps just how deep and talented its lineup is.
"We're playing well, but there's always room for improvement, always things we can do [better]," Staal said. "But I feel like that comeback feeling is there, that we're never really out of a game and there's always an opportunity to win games.
"We haven't really dominated games, but we've done a lot of good things."