Sensitive emails between NHL brass have revealed a league struggling to figure out the future of fighting amid mounting concern over concussions and addictions. They have also given new ammunition to critics who say fighting should be banned outright from the game.

The emails were among hundreds of documents unsealed by a U.S. federal court this week, part of an ongoing class-action suit against the NHL.

In the exchanges, top league officials discuss the connection between fighting, mental health struggles and what one executive calls "personal tragedies."

"Frankly, it's clearly getting harder and harder to defend fighting in hockey," says Arthur Caplan, a bioethicist at New York University who has written extensively on concussions in sport.

"We've known for some time that it's dangerous, but now there's proof that top NHL officials were discussing and acknowledging how it can affect players years down the road in very troubling ways. But they've let it continue."

Perhaps the most provocative conversation is from early September 2011, shortly after three fearsome enforcers — Derek Boogaard, Rick Rypien and Wade Belak — were found dead over the course of four months. Their deaths all appeared at least partly connected to their years of bloody scrapping on the ice.

NHL Commissioner Gary Bettman has resisted calls to end fighting in hockey, saying it's always been part of the game. (Christinne Muschi/Reuters)

In the email exchange, NHL commissioner Gary Bettman says: "An interesting question is whether being an NHL fighter does this to you (I don't believe so) or whether a certain type of person (who wouldn't otherwise be skilled enough to be an NHL player) gravitates to this job (I believe more likely)."

Deputy commissioner Bill Daly responds, "I tend to think it's a little bit of both. Fighting raises the incidence of head injuries/concussions, which raises the incidence of depression onset, which raises the incidence of personal tragedies."

This is a departure from the position the league has taken publicly, which generally has been to repeat that there's just not enough evidence yet to know, conclusively, that the burdens of enforcers lead to both physical and emotional struggles off the ice.

But behind the scenes, there has clearly been a push from some camps for the NHL to do more.

Brendan Shanahan, the president of the Toronto Maple Leafs who was then the NHL's top disciplinarian, wrote in the email chain that Belak's death was an opportunity "to get the support to finally say enough."

Shanahan after Wade Belak’s suicide: "it goes back to concussions” + action to curb fighting “the right thing to do" <a href="https://t.co/xu1GYiZODP">pic.twitter.com/xu1GYiZODP</a> —@TravisSBN

"Regardless of what the specific reasons are that drove Wade into this, I think it simply goes back to concussions and brain injuries," he wrote.

Shanahan went on to say that "maybe it's time to propose increases in the penalty for fighting ... It's only a matter of time before the CHL and other feeder leagues do it. Let's be first. I believe it's the right thing to do."

Game is evolving away from fighting

But even if the NHL has yet to act definitively, fighting has become a more marginal aspect of the game, and the role of the traditional enforcer has been reduced to a vestige of hockey's past.

Hockey has evolved toward speed, skill and more complex systems. Those changes, along with the salary cap, mean that teams need all four lines to produce.

Some NHL executives, as well as team owners, worry that ending fighting will drive away fans and revenue, says Arther Caplan, a bioethicist who has been a vocal critic of the league on this issue. (Adam Hunger/Reuters)

"That's generally a good thing, but if we're saying that brawling is less and less central to how the game is played, why not just get rid of it outright? Are we not at that point yet?" asks Caplan.

The short answer seems to be no. Surveys have shown that many fans want fighting to stay. And there are those within the hockey world that maintain it's an ugly but essential element of the game.

The argument goes that fighting is a form of self-policing — that the threat of an enforcer's retribution prevents other guys from playing dirty or targeting skilled players.

Derek Boogaard's death on May 13, 2011, was ruled accidental, the result of a toxic mix of alcohol and the powerful pain killer oxycodone. Boogaard, right, was once the NHL's most fearsome enforcer. (Matt Slocum/Associated Press)

In a recent op-ed titled "End to fighting would not make hockey a safer game", former NHLer Bobby Smith pointed to studies that found fighting accounts for only a fraction of all concussions in pro hockey. Elbows to the head and hits from behind, for example, do far more harm to players' brains, on average, than fights.

The damage done is worth the damage prevented, his reasoning implies, and it makes for a better game.

'The NHL has to step up'

Even a retired enforcer now dealing with some of the consequences of a violent career isn't sure the NHL should do away with fighting.

"We're grown men and we're out there and we know our role," says Ryan VandenBussche, who racked up more than 230 fights at the junior and pro levels, spending nine years in the NHL.

"To take fighting out is changing the game of hockey ... I think there is a limited place for it. Maybe there should be stricter punishments."

The NHL instituted a rule before the 2013-2014 season that players must keep helmets on during fights, ostensibly to protect their heads if they fall lifelessly to the ice after being knocked unconscious in a fight. (Marc DesRosiers/USA Today Sports/Reuters)

VandenBussche is not part of the group of former players now suing the league. That suit alleges the NHL put profits above the safety of players and failed to warn them about the long-term dangers of repeated concussions.

But he says the NHL needs to "do a better job looking after its players, guys who need a little help after.

"The bottom line is that the NHL has to step up for the guys who are hurting."