Now 59, Carson said that he recognized even while he was playing that he was having "some neurological problems, but I couldn't really put my finger on exactly what it was."
Carson appears in "League of Denial," which until late August was considered a joint production of "Frontline" and ESPN (more about that in a bit), but he's far too well-spoken and healthy-looking to be the face of anyone's nightmares about brain damage. He's there, at least in part, to talk about Mike Webster, the former Pittsburgh Steeler whose 2002 death at age 50 became the catalyst for investigating the possible link between football and a specific kind of brain injury.
I'm glad, though, that Carson spoke to us about his grandson - his concern involves a decision a lot of parents face and it's one that a show like this might actually affect.
As controversial as it is, this "Frontline" is probably not going to advance the ball much for those who think that football's too dangerous for the grown men who in some cases are paid millions to play it.
As Upton Sinclair observed, "It is difficult to get a man to understand something, when his salary depends on his not understanding it."
That may be the simplest way to explain the NFL's long, long dithering on the issue of concussions, which, along with the circumstances leading to its recent $765 million settlement with former players, is discussed exhaustively in "League of Denial." And maybe it explains, too, ESPN's decision, announced in late August, to have its collaboration credits removed from the documentary on the grounds that it didn't have editorial control.
The two-hour piece is still heavily based on the work of two ESPN reporters, Mark Fainaru-Wada and Steve Fainaru. (The pair, who are brothers, also have a book, League of Denial: The NFL, Concussions and the Battle for Truth, that comes out today.) But ESPN, which reportedly pays the NFL $2 billion a year for "Monday Night Football," is no longer an official collaborator.
Read into that what you will, but as someone who, honestly, doesn't pay much attention to football (Go Eagles!) and hadn't followed Webster's career or its extremely sad postscript, I was more struck by what scientists appear to be learning about the dangers to young players involving, possibly, even knocks on the head that don't result in actual concussions.
Not that Webster and the science that began with his autopsy, performed by a Nigerian-born medical examiner in Pittsburgh who probably knew even less about football than I do, don't make for a fascinating story.
"If Webster's brain had not been examined, I don't honestly think that we would be where we're at today," says Steve Fainaru.
Webster himself might have wished that the rest of him had been examined a little less completely - there are photos that appear to be from his autopsy, and one son recalls, wryly, his father's insistence on using Super Glue to return his missing teeth to his mouth, while another says that Webster used duct tape on the cracks in his feet.
The ex-Steeler's story is so colorful, in fact, that it threatens to obscure the one that "Frontline" and the Fainaru brothers seem to be trying to tell, of a sport that's long been celebrated for its violence being asked to confront the damage that may linger long after the players have left the field.
On Twitter: @elgray