The family of former NHL player Steve Montador, who died earlier this year, are suing the league over accusations it failed to inform him about the risk of long-term brain damage.
The Canadian, who played 10 seasons with six teams, was found dead in his home in Toronto in February aged 35.
According to court papers, he had 15 documented concussions in his career.
The suit was filed on behalf of his son, Morrison, and other family members by his father, Paul.
Montador Sr said his son suffered from depression, memory problems and erratic behaviour and was involved in 69 on-ice fist fights during his NHL career.
"During regular-season NHL games, pre-season NHL games, NHL practices and morning skates prior to NHL games, Steven Montador sustained thousands of sub-concussive brain traumas and multiple concussions, many of which were undiagnosed and/or undocumented," claimed the suit.
According to Associated Press, several years before his death, the player had decided to donate his brain to the Canadian Sports Concussion Project.
In May, three months after his death, researchers confirmed Montador's brain had chronic traumatic encephalopathy (CTE), the brain disease that has been linked to repeated head trauma.
|Montador's NHL career|
|2002-2005: Calgary Flames|
|2005-2008: Florida Panthers|
|2008-2009: Anaheim Ducks|
|2009: Boston Bruins|
|2009-2011: Buffalo Sabres|
|2011-2012: Chicago Blackhawks|
"The NHL continues to ignore the lasting problems caused by multiple head traumas suffered by its players," Paul Montador said in a statement.
"Tragedies like that of my son Steven will continue until the problem is addressed. The NHL knows, but denies, that years of repeated head injuries cause long-term brain problems."
NHL commissioner Gary Bettman declined to comment on the case, and said the league was not going to litigate the case publicly. Deputy commissioner Bill Daly said in an email the "claims made in the lawsuit are without factual or legal merit".
In April, the National Football League reached a settlement of a lawsuit brought by former players over concussions that could cost the NFL $1bn (£665m) and a US federal appeals court is considering whether the settlement figure is sufficient.
In Britain, rising fears over head injuries across all sports prompted the Football Association to issue new guidelines earlier this month to all involved with the game on how to deal with concussions.
World Rugby's chief medical officer Martin Raftery recently told the BBC the sport's rules may have to change to reduce concussions. with reported concussions doubling in five years.