Current and former players had strong reactions to a top NFL official acknowledging for the first time a link between football-related concussions and the degenerative brain condition known as CTE (chronic traumatic encephalopathy).
The testimony from Jeff Miller, the NFL's senior vice-president for health and safety, came during a hearing before the United States House of Representatives' energy and commerce committee on Tuesday.
During the forum on concussions and head injuries, Miller said there was a link between CTE and football, based on Boston University research showing 90 out of 94 NFL players' brains examined after death had signs of the disease.
Miller also said several questions need to be asked on the subject, and players took to social media to air their response.
Chris Kluwe, a former punter for the Minnesota Vikings, mocked the NFL's concession in a tweet.
"NFL also admits 'water likely wet,' as well as 'sky possibly blue on occasion,"' Kluwe (@ChrisWarcraft) tweeted yesterday.
A tweet sent from Cleveland Browns wide receiver Brian Hartline's Twitter account cited the Boston University data. "Boston University researchers have found evidence of CTE in 90 of 94 former NFL players studied," Hartline tweeted.
"Ya there's a link."
Player safety has long been a topic of concern in the league but focus intensified over brain injury last year.
The 2015 film Concussion, as well as the August 2015 posthumous induction of linebacker Junior Seau into the Pro Football Hall of Fame, brought more attention to the issue.
Seau committed suicide in 2012 and a study of his brain later showed he had CTE.
Ravens' tackle Eugene Monroe (@The SeventyFifth) also tweeted a link to an article about Miller's testimony.
Later, he tweeted: "If you're a player and you see this. Junior Seau and many others. Yes, it can be us too."