The immediate effect is hard to miss.
Wrench guys such as Sidney Crosby, Evgeni Malkin, Kris Letang and Zbynek Michalek, among others, from a team's lineup for extended stretches, and it will have an impact.
And not a positive one.
Players like those are not pulling down seven-figure salaries simply because management was feeling generous when their contracts were being negotiated.
But there can be an insidious, if somewhat less obvious, effect on a team when it has had so many prominent players out of its lineup for so long, the way the Penguins have the past season and a half.
Although they have been remarkably competitive in that time, finishing in a tie for third in the NHL's overall standings in 2010-11 and starting 17-10-4 this season, it hardly seems out of the question that the guys who are not hurt could begin to wear down, physically and/or mentally, eventually.
Not, mind you, that the Penguins are giving even cursory consideration to the idea.
"You can get discouraged, but that's just because you always want those guys in," defenseman Paul Martin said. "You want your top lineup. You know how good you can be when you have them.
"It's too hard to tell what will happen in the long run. For now, you go out when you're told and do the best you can and see what happens."
The Penguins best has been fairly good to this point. Despite losing 151 man-games to injury as they prepare to face Ottawa 7:38 p.m. Friday at Scotiabank Place, they have remained in contention for first in the Eastern Conference because numerous players who have taken on expanded roles have responded well to those extra responsibilities.
"Most guys want more ice time," forward Craig Adams said. "There are probably only a few guys who couldn't really take any more, because they've already got so much."
Eight players sat out the Penguins' 4-1 loss Tuesday to Detroit because of injuries; four of them -- Crosby, Michalek, Letang and Robert Bortuzzo -- have been diagnosed with a concussion or are displaying symptoms associated with one.
Concussions have become a near-epidemic in the NHL and, unlike some injuries, cannot be blamed on suspect conditioning. There is no known way to train to avoid them, unless that training involves a way of ducking all the contact inherent in the game.
"Concussions aren't something where guys aren't in good shape, or guys aren't working out," forward Pascal Dupuis said. "Most of the time, it's fluke incidents."
In the case of the Penguins, frequent fluke incidents.
"Obviously, the head injuries are beyond your control, for the most part," Adams said. "It's not like we've got 10 guys out with pulled groins."
Michalek, who has not played since Nov. 26, seems optimistic about getting back into the lineup Friday, but looks to be the only injured guy on the cusp of returning.
The Penguins had a week in late November when their lineup of choice was largely intact, and they defeated the New York Islanders, Ottawa and Montreal, while losing to St. Louis.
Letang and Michalek were hurt against the Canadiens, however, triggering another long stretch in which the Penguins will not be able to dress the 20 players they would under ideal circumstances.
"At some point, would we like to have everyone?" Adams said. "Absolutely. I think we have a pretty great team in here. But, at the same time, I don't think anyone's feeling sorry for themselves in here."
Only seven players have dressed for each of the first 31 games, and no fewer than 28 have pulled on a Penguins sweater in the first two-plus months of the season.
"We're testing our depth," winger Steve Sullivan said. "We have a lot of good hockey players on this team. The 20 guys who put the jersey on are expected to do a job and do it well."
Martin joined the Penguins as a free agent in the summer of 2010. Since then, their preferred lineup essentially has been together for all of four games and parts of two others.
How many times that will happen again -- if ever -- before his contract expires in 2015 is tough to predict.
"The longer it goes, the less likely it becomes," Martin said. "[With] it being earlier in the year, it's just something where you hope that toward the end, everyone will be back and healthy.
"It would be ideal to have everyone back as soon as possible, but that's just the way it is. For now, it's just trekking along and trying to do the best we can."
Dave Molinari: Dmolinari@Post-Gazette.com or Twitter @MolinariPG. First Published December 15, 2011 5:00 AM