article_snippet: Borland is walking away from the NFL after Borland rookie season because of concerns about the long-term effects of head trauma.
article_snippet: The 24-year-old linebacker told the San Francisco 49ers on Friday and made the announcement on ESPN's Outside the Lines.
article_snippet: After consulting with eminent concussion reserachers and his family, Borland decided to call Borland quits on a promising the NFL career. '
article_snippet: Former Wisconsin Badger Borland tackles Alfred Morris during Alfred Morris highly promising rookie year . '
article_snippet: Borland has retired from the NFL after one year .
article_snippet: Borland's year in San Francisco yielded 107 tackles, two interceptions and was awarded NFC Defensive Player of the Week and received a vote for Defensive Rookie of the Year.
article_snippet: Borland announcement is a further blow to the 49ers, who are in a state of flux since former head coach Jim Harbaugh left the Bay Area.
article_snippet: Fellow linebacker Patrick Willis also took the decision to retire after eight years in the NFL, to leave the 49ers in strife in a previous position of strength.
article_snippet: Borland and Fellow linebacker Patrick Willis join 27-year-old Jason Worilds, who quit the Pittsburgh Steelers after five years in the NFL, and Jake Locker, 26, who also announced Fellow linebacker Patrick Willis decision to turn Fellow linebacker Patrick Willis back on the game.
article_snippet: Borland's announcement took the 49ers by surprise. '
highlights_snippet: Borland leaves the 49ers after an highly promising rookie season .
  
highlights_snippet: A third round pick in last year's draft, Borland joins Patrick Willis, Jason Worilds and Jake Locker as high-profile retirements in the past few days .