BERKELEY, Calif. -- San Francisco 49ers linebacker Chris Borland, one of the NFL's top rookies last season, told "Outside the Lines" on Monday that he is retiring because of concerns about the long-term effects of repetitive head trauma.
Borland, 24, said he notified the 49ers on Friday. He said he made his decision after consulting with family members, concussion researchers, friends and current and former teammates, and studying what is known about the relationship between football and neurodegenerative disease.
"I just honestly want to do what's best for my health," Borland told "Outside the Lines." "From what I've researched and what I've experienced, I don't think it's worth the risk."
Borland becomes the most prominent NFL player to leave the game in his prime because of concerns about brain injuries. More than 70 former players have been diagnosed with progressive neurological disease following their deaths, and numerous studies have shown a connection between the repetitive head trauma associated with football, brain damage and issues such as depression and memory loss.
Chris Borland prior to the game against the Seattle Seahawks at Levi Stadium on Nov. 27, 2014.
"I feel largely the same, as sharp as I've ever been, for me it's wanting to be proactive," said Borland. "I'm concerned that if you wait till you have symptoms, it's too late. ... There are a lot of unknowns. I can't claim that X will happen. I just want to live a long healthy life, and I don't want to have any neurological diseases or die younger than I would otherwise."
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