Shane Dronett tells ESPN that `` I know this is right for me '' San Francisco 49ers linebacker quits , citing players with concussion disorder , says he wants to `` be proactive '' Some former players who suffered from conditions related to concussions have committed suicide .
Chris Borland tells ESPN that `` I know this is right for me '' San Francisco 49ers linebacker quits , citing players with concussion disorder , says he wants to `` be proactive '' Some former players who suffered from conditions related to concussions have committed suicide .