Chris Borland, an up-and-coming young linebacker for the San Francisco 49ers, says he has decided to retire from the NFL because he's worried about his long-term mental health.
According to a report by ESPN's Outside the Lines, Borland, who's just 24 years old, is quitting the league "because of concerns about the long-term effects of repetitive head trauma."
He's quoted in ESPN saying, "I just honestly want to do what's best for my health. From what I've researched and what I've experienced, I don't think it's worth the risk. ... For me, it's wanting to be proactive, I'm concerned that if you wait till you have symptoms, it's too late."
According to a CBS sports writer, Borland suffered two diagnosed concussions, with the last one coming while he played high school football.
Borland was a promising young talent who really broke out as a starter in the second half of last season; he recorded 107 tackles and one sack.
The 49ers released a statement saying they supported his decision, even though it caught them off-guard.
"[Chris] was a consummate professional from day one and a very well respected member of our team and community. ... We will always consider him a 49er and wish him all the best."
On a larger scale, Borland's retirement will likely stir more conversation about head trauma in the NFL, especially considering he decided to hang up his cleats at such a young age.
"He was a force for the 9ers last year. ... So the idea of a player of Borland's age at just 24 ... it's a large moment around the NFL for somebody deciding to quit the game because of this issue," ESPN Investigative Reporter Mark Fainaru-Wada said.
Last year, the NFL finally agreed with research data that says nearly one-third of all retired football players develop some sort of long-term mental heath problem.
This video includes images from Getty Images.