Bob Stein can still indulge in a little gallows humor. "The good news," he said, "is that I can't remember how many concussions I had."

The attorney and former Minnesota Timberwolves president spent eight years knocking heads as an NFL linebacker. One injury he does recall just barely happened in 1971, when his Kansas City teammate Willie Lanier tried to stop O.J. Simpson on a kickoff return by swinging a fist at him. Lanier missed and hit Stein instead, knocking him unconscious.

A doctor examined Stein on the sideline and told him he might have a concussion. As was the custom at the time, he asked if Stein wanted to return to the game; as was the custom, Stein said yes. He had no idea he had a skull fracture until 15 years later, when a sinus infection slipped through the break and morphed into a near-fatal case of spinal meningitis.