Steve Young on the ESPN set for the 2009 NFL Draft. Photograph by Marianne O’Leary

A few days before Super Bowl 50 this Sunday comes sobering news: Onetime Oakland Raiders quarterback and Super Bowl MVP Ken Stabler had CTE, or chronic traumatic encephalopathy, a kind of dementia related to concussions and sub-concussive hits.

Stabler, who died in July of cancer at age 69, left his brain to be studied by researchers in Massachusetts.

Of the 91 brains of ex-players that have been tested – you can’t test for this except after death – 87 had brain trauma.

There are two things of note here. One is that Dr. Ann McKee, a neuropathologist and expert in neurodegenerative disease at Boston University School of Medicine, and her team could immediately see the degeneration in Stabler’s brain. (In contrast, Dr. Bennet Omalu, who first documented CTE, didn’t discover the disease until he studied slices of former Pittsburgh Steeler Mike Webster’s brain under a microscope.) Does that mean that CTE is even more aggressive than we thought?

The other is that Stabler wasn’t an enforcer or a center like Webster, who took a lot of punishment. He was the most protected guy on the team, the brains, the lieutenant. He was the quarterback.

And yet, quarterbacks take a lot of sacks. Look at former San Francisco 49ers’ quarterback Steve Young, who appears in the riveting book and PBS’ “Frontline” documentary “League of Denial: The NFL’s Concussion Crisis.” He’s not even sure how many concussions he’s had. Old ladies used to come up to him and beg him to save himself. (A league and Super Bowl MVP, he retired in 2000 at age 38.) Young, 54, an ESPN analyst who can speak for 45 minutes without notes, is fine. On the other hand, his contemporary, former Chicago Bears’ quarterback Jim McMahon, 56, was diagnosed with dementia a few years ago.

As Dr. McKee said of Stabler’s case, "It shows that even playing quarterback – and if you play a number of years – that you're at risk for developing this disease."