Adrian Robinson Jr., a former player for four N.F.L. teams who killed himself in May at 25, had a brain disease that has been linked to repeated blows to the head, researchers confirmed Wednesday.
The diagnosis of chronic traumatic encephalopathy was made by the Boston University-affiliated Concussion Legacy Foundation, which studied the brain of Robinson, a Harrisburg, Pa., native who played for Temple in college and with Pittsburgh, Denver, San Diego and Washington.
A family lawyer, Ben Andreozzi, said Robinson had several concussions in his two seasons in the N.F.L.
Thousands of former players have sued the N.