Former San Francisco 49ers tight end Greg Clark has died at 49, his family said Friday. Though family members did not specify a cause of death, they did say he had shown signs of chronic traumatic encephalopathy, the brain injury common among NFL players. The family’s statement reads, “His recent suffering from CTE symptoms cannot extinguish the breadth and depth of his impact on us and others, and we are forever grateful for the time we have had with him. It is our hope that through further research we can gain more knowledge surrounding CTE.” Clark played four seasons in the NFL with the 49ers beginning in 1997 after playing for Stanford. He is survived by his wife and three sons.