What Killed Lou Gehrig?

Maybe not what you might think.

http://www.guardian.co.uk/science/2010/aug/17/lou-gehrig-disease-baseball-death

Here is an interesting piece that looks at brain injury of various athletes and causes of death. Recent research has indicated that even minor concussions can add up to a significant amount of cumulative damage.

Could Mr. Gehrig's death actually have been from repeated blows to the head caused by baseballs?