Like long relievers in baseball or the punt-coverage unit in football, the fourth line on a hockey team is essential, yet often overlooked.
But on a championship-caliber team like the Blackhawks, where everything is dissected, bisected and even trisected, when the fourth line is underperforming -- especially in the playoffs -- everyone realizes it.
Joel Quenneville must have thought so as well, because at practice Thursday the Hawks coach had the old gang -- Ben Smith, Marcus Kruger and Brandon Bollig -- back together for the first time since the regular season.
The hope is that the trio, if it stays together to start the conference finals, will perform as well as it did during the regular season when the Hawks were consistently rolling four lines.
"That line, for the majority of the season, was a big part of our team success," Quenneville said. "It gives you the strength in the checking role, dependability on faceoffs and matchups as well.
"We'll play out how things evolve in the next round, but they had stretches in the season where they were in the opponents' end for a big stretch of games and a big stretch of the season with that consistency."
Bollig, who is back for the start of this series after serving a two-game suspension for his hit on Minnesota's Keith Ballard, can't wait for the reunion tour to kick off.
"I've sure missed it," he said. "Obviously we played together a good portion of the season and we had a nice roll there where we kind of found our niche together.
"So the fact that we were out there together … and hopefully it stays that way for the game -- and that's what gets us good quality minutes and playing a quality role."
Their teammates seem pumped to watch that line get back at it.
"They've been great all year," Brandon Saad said. "They mixed it up a little in the playoffs here and with suspensions and things like that.
"Those three play great together for some reason. He went back to them, and we'll see how it goes throughout the series."
In Bollig's mind, the reason for the fourth line's success during the regular season was pretty basic.
"There's no secret that the more you play with guys the more comfortable you are with them and the more familiar you are with the way they play," he said. "Us three obviously are comfortable with each other, and if we stay together, then I think we work well together.
"That's the reason we stayed together for so long. Hopefully it stays that way."
Under Quenneville, who's not afraid to switch things up on the spur of a moment, usually as long as a line is performing up to expectations, whatever that may entail, it will remain intact.
"Our role during the season, we kind of knew we were going to be out there against another team's top one or two lines," Bollig said. "So you kind of know when they come over the boards, so are we.
"I don't know if that's the role we're going to play again, hopefully, but if it is we're going to be ready for that."
And Quenneville knows one thing for sure about his trio of Smith, Kruger and Bollig, if they're hitting on all cylinders …
"They can make a difference."