The average NFL career lasts 3.5 years. Junior Seau, one of the greatest linebackers in the history of the NFL, played for twenty—and San Diego, where he starred most of those years for the Chargers, was his city as much as New York is Derek Jeter's. Seau invested in San Diego both as a businessman and as the head of a foundation serving at-risk kids. But after retiring as a very wealthy man in 2010—he earned more than $50 million over the course of his long career—he began to behave uncharacteristically.

Seau was a star linebacker for twenty seasons, primarily with the San Diego Chargers,where he was legendary for his seeming indestructibility.
He withdrew from family and friends. He made terrible business decisions. He abused pills. He drank. He gambled away terrifying sums. It was evident to those who knew him well that he was struggling, but no one foresaw his suicide on the morning of May 2, 2012.
Eight months after his death, the scientists who examined his brain announced they had found evidence of CTE (chronic traumatic encephalopathy), a dire neurological disease linked to concussions, which has been a factor in the deaths of many other NFL players. It's impossible to pinpoint the degree to which CTE drove Seau's rapid decline; the disease has been connected to depression, insomnia, emotional withdrawal, and compulsive behavior—all of which afflicted him. But there's one thing everybody close to Seau agrees on: In his final years, Junior was no longer the Junior they had known and loved.
···
1. The Man Who Loved to Hit
Natrone Means (San Diego Chargers running back, ex-teammate): God Almighty, he was fast. He was strong, man. He was hands-down the best football player I ever played with.
Aaron Taylor (Chargers guard, ex-teammate, friend): Any time you play a sport that requires an ambulance to be on-site, it's inherently a fucking dangerous game, right? "Getting your bell rung" was the euphemism, and I think we all took pride in it. If you didn't light somebody up or get lit up in a collision, there was a sense that we weren't doing our jobs.
Warren Moon (NFL Hall of Fame quarterback, friend): You have two guys running full speed into each other and butting heads. And that's during practice. You don't do anything like that in a game.

Seau at USC with the Chargers.
Jay Michael Auwae (friend): I once asked Junior what the biggest hit was that he could recall. He said, "Buddy, it wasn't in a game. It was in practice. Natrone Means was talking trash; I was talking trash. I said, ‘Bring it on!' " Junior said Natrone hit him so hard, and he hit Natrone so hard, that they both were knocked out.
Means: I don't recall this. Maybe it was such a big collision that it's gone from my memory. But I can remember countless times I've seen Junior just smash guys out there. Fights would break out all the time. You want to make a name for yourself. And if you have a name, you want to prove why you have the name.
Taylor: I personally watched him take multiple injections, because he was in front of me in line for them. The 'Caine sisters: Marcaine, lidocaine. Toradol and steroidals to calm down inflammation. I can't say for certain what it was he took, but I would imagine they're not going to give him anything different than what we would've gotten for similar injuries. It was what you did.
Means: I remember him playing in the AFC Championship game [in 1995] with the pinched nerve, man. I mean, sixteen tackles. With a pinched nerve. God Almighty. Never coming out of the game.
Mark Walczak (Chargers tight end, ex- teammate, friend): I couldn't believe the number of surgeries he had. There were like 15 or 16.
Means: It was the "smelling salts and get back in there" generation.
Taylor: You cannot show vulnerability in the locker room. It's despised. Who wants to be a bitch?
Moon: One thing I read that was peculiar to me—he had never been diagnosed with a concussion. That tells me he wasn't reporting what was wrong with him. For a guy that played linebacker for twenty years, somewhere in there he would've had a concussion.
···
2. "What Do You Do with Your Day Now?"
As early as the mid-1990s, when Seau was in his twenties, he was privately complaining of headaches and bouts of dizziness. He also developed insomnia and began to pull away from his wife (they would divorce in 2002) and children. But there were no signs of that man when Seau announced his retirement on August 14, 2006. Instead he struck a more hopeful note: "I'm not retiring," he said. "I am graduating." Just four days later, he changed his mind and signed with the New England Patriots, where for the next four seasons he chased after an elusive Super Bowl ring. In January 2010, a few days before his forty-first birthday, he retired for good. "I'm going to surf," he said.
With his ever present ukulele, Seau was a fixture on the streets and beaches of Oceanside, his suburban San Diego hometown. But soon he began drinking heavily to cope with his insomnia, while also taking Ambien, a sleeping medication prescribed to him by the controversial former Chargers team physician David Chao (who has since, in an unrelated case, been found liable for malpractice). A downward spiral was taking shape: Seau's worsening health affected his business acumen—and when he made bad financial decisions, he would try to gamble his way out of them