Former Chicago Bears running back Thomas Jones, who played 12 seasons in the NFL, told ESPN.com he plans to donate his brain to the Sports Legacy Institute to be studied for chronic traumatic encephalopathy after he dies.

Jones said he did not know how many concussions he suffered and is concerned for his future health. He added that he was affected by the suicide for former Bear Dave Duerson, who was found to have CTE after his death.

"His suicide, you see it on TV and it's just news," Jones said. "But to us, it's more than that."