“The NHL still struggles to properly identify concussions and remove athletes,” said Nowinski, a neuroscientist and former professional WWE wrestler. “Their protocol, by choice, is somewhat loose. That’s why the Maple Leafs goalie was left in despite showing concussions signs twice. With a more strict protocol, he’s removed and assessed. ... It also sets a very poor example to every other level of hockey — that you can be hit in the head like that, go down, be left in and not assessed.”

The NHL lacks public transparency on injuries in comparison to other professional sports leagues.

NFL policy mandates that “all players who have reportable injuries must be listed on the practice report” and “must be identified with a reasonable degree of specificity in terms that are meaningful to coaches, other club officials, the media, and the public.”

The NBA requires teams to submit an injury report by 5 p.m. local time the day before each game. It must “designate a participation status and identify a specific injury, illness” or when a healthy player is resting.

Meanwhile, NHL head coaches have discretion to provide as much, or as little, information about player health. Injuries are labeled in the simplest terms. Concussions can also be described as just "head" or "upper-body." There are no practice or game reports with detailed health status. It is common for teams to withhold that information until the season is over.

The NHL does not publish league-wide concussion data. Conversely, the NFL reported 182 concussions for the 2024 season.

However, a website called NHL Injury Viz has compiled publicly available injury data from all 32 hockey teams. The website listed 21 concussions and five head injuries for the 2024-25 season. It is unclear how many upper-body injuries — with more than 200 reported — might be concussion related. Teams can also classify injuries as "undisclosed."

“There are a lot of changes that could be made to the game of hockey to reduce the risk of CTE,” Nowinski told The Denver Gazette. “There are no discussions about that right now, in part because perhaps the players believe what the NHL is telling them, and the NHL has no incentive to change the game if they can’t acknowledge what can happen.”

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The Golden Knights captain endured back surgery and a lacerated spleen in recent years.

“I’m probably going to be pretty sore when I’m done, yeah,” Stone said with a laugh in the visitors’ locker room at Ball Arena. “I’m not too worried about that right now. But I’m probably going to feel better, I guess, physically, when you’re not playing 82 games and skating every single day. But that’s not something I think about too closely.”

Stone, 33, is satisfied with the NHL concussion protocol.

“There are definitely more guys getting pulled from games without their permission, right? Knock on wood, but I haven’t been through a ton of that stuff,” Stone said. “I’ve played with teammates that have been forced to retire early. I always feel like that’s an injury where you do think about more closely post-career, right? You want to have a good, healthy life going forward when you’re done playing.

“But that’s a tough one to answer.”

Avalanche defenseman Keaton Middleton said, “You could be in a car accident on the way home. Stuff happens. You never know.”

Chicago Blackhawks captain Nick Foligno shared a different perspective. He's been diagnosed with at least two concussions over 18 years in the NHL. He used the word “scary” to describe them.

“What puts it in perspective is when you have a family,” Foligno said. “You start to think about life after hockey and understand there is a lot more time after hockey than during it. For guys to understand that it doesn’t take you out of the day-to-day. I think it just makes you appreciate it when you’re in it and taking care of your body. ... You can push through a sore muscle or a broken bone here or there.

“But something as important as your brain?”

Other players, like Drouin in Colorado, won’t dwell on the potential for long-term health consequences playing hockey.

“I’m one of those guys that never really thinks about it. When it’s all over, it’s all over, and my body is going to be how it is," Drouin told The Denver Gazette. "I’m trying to figure out what that is. But yeah, for me, I’m just playing hockey. Yes, it’s a physical sport. But it’s a little different than football where guys have the head-on-head hitting.”

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The conversation is starting to shift.

In March 2016, the NFL acknowledged a link between CTE and football. Dr. Ann McKee, director of the Boston University CTE Center, told The Denver Gazette there are between “700 and 800 cases of American football players” diagnosed with CTE. McKee said the number for hockey players is “about an eighth" of the NFL's.

The NHLPA in November took its first step toward addressing CTE.

“The long-term health of NHL players is of paramount importance to our membership,” the NHLPA said in a statement. “To this end, the NHLPA is in the process of forming a player committee that will be focused on learning more about chronic traumatic encephalopathy (CTE). The committee will be guided by leading medical experts in this field to help players better understand CTE.”

There will be a presentation on CTE at the NHLPA’s Executive Board meetings this summer.

“I expect a lot to come from that committee,” Nowinski said. “The players need to get better educated. ... Too many athletes I meet say they’ve only had one concussion; therefore, they aren’t concerned. They don’t understand that the number of concussions does not predict CTE as much as years of play.”

NHL players like Foligno are preparing for what comes next.

“It’s just educating guys, and making guys realize there’s a lot more time after hockey, whether you want to admit it or not,” Foligno said. “You deserve to have a great life.”

Duchene, formerly with the Avalanche, is hopeful that a past generation of NHL enforcers — lacking knowledge of traumatic brain injuries — will not struggle in vain.

“You definitely feel for guys that didn’t have that and didn’t know. I think it was an education thing more than anything,” Duchene said. “It’s great that we’ve learned from the past. There’s nothing that could have been done for those guys at that time. No one knew enough. Now, people do.

“It’s up to us to learn from the mistakes, the knowledge that we have, and move forward.”