Intro:

San Francisco 49ers linebacker Chris Borland spoke on Tuesday about his decision to retire from the NFL because of a fear of head trauma.

Script:

SOUNDBITE (English): Chris Borland, Former San Francisco 49ers linebacker:

"I think it was a combination of a number of things. It's a unique decision to me. I had done a lot of research of what I've experienced in my past projected to being the linebacker that I wanted to be and for me it wasn't worth the risk. Not to say that its a certainty, I could be wrong, I hope I am wrong obviously, but for me it was the right decision."

SOUNDBITE (English): Chris Borland, Former San Francisco 49ers linebacker (on what the deciding factor was):

"Brain disease frankly. Not to say that players who have played for a long time who were physical players that its a forgone conclusion, but to me, it just, the chance of that happening was more of a negative than the positive that my potential career could be."

SOUNDBITE (English): Chris Borland, Former San Francisco 49ers linebacker:

"One instance in particular in camp where I thought I sustained probably a mild concussion and just played through, what football players refer to as a ding or getting your bell rung and that was the moment where it went really went differently for me."

SOUNDBITE (English): Chris Borland, Former San Francisco 49ers linebacker:

"That happens a lot in a football career and I had been relatively healthy from that stand-up for the nine years I played football up until that point. But it was kind of the realisation, you know, I had just started my professional career, and am I going to go down this road, am I going to commit the prime of my life to something that could ultimately be detrimental to my health? That just triggered my thinking and changed the way I viewed the risks."