Two members of the 49ers' famed "Million Dollar Backfield" who died within months of each other this year will have their brains examined by researchers at Boston University that are studying head injuries in sports. Joe "the Jet" Perry died in April at the age of 84 and John Henry Johnson died last week at the age of 81. Their families have agreed to let their brains be examined by the Center for the Study of Traumatic Encephalopathy, the San Francisco Chronicle reported. CSTE is a collaboration between Boston University Medical School and the Sports Legacy Institute that is attempting to address what it calls the "concussion crisis" in sports.