So again the sporting world is confronted by tragedy, and we are left to debate and contemplate.

A gunshot. Disbelief. A haunting refrain, the Beatles singing, "I read the news today, oh, boy, about a lucky man who made the grade ..." A lucky man who took his own life.

All too prophetic. All too real.

The autopsy was announced Thursday, telling us what we already knew: Junior Seau committed suicide. Junior Seau, football star, entrepreneur, icon, died from a self-inflicted gunshot wound to the chest.

What we don't know is why, although in time we may learn.

On one TV network, they were talking about head trauma in pro football. On another, they were questioning the commissioner of the NFL's authority to suspend players for intentionally trying to injure opponents.

It's a rough game. No one has attempted to tell us otherwise. But how rough? Do all those tackles and blocks lead to neurological problems? Dozens of lawsuits contend they do.

Three suicides by retired NFL players in the last 15 months. Dave Duerson, in February 2011, whose note said he wanted his brain studied. Ray Easterling two weeks ago. Now Seau, 43, who left no explanation.

Only Monday, Seau played in a charity golf tournament and was in a group with Hall of Fame receiver Jerry Rice, who told ESPN that Seau was upbeat.

"He said everything was going great,'' said Rice. "He was such a happy person."

Or so it seemed. Football has become more than a game. It has become a worry, with fines for bounties and fears of concussions.

Harry Carson, the onetime New York Giants linebacker, told the New York Post that unlike the rest of us, he was not shocked by Seau's death.

"I knew years ago that there would come a point in time where there would be guys having these neurological issues,'' said Carson, "that players were going to be committing suicide. ... You can't really explain what you're dealing with."

Such a bizarre juxtaposition of events, a man who may - may - have received too many blows to the brain shoots himself, and the same day the NFL punishes four players with the New Orleans Saints in 2009 for taking part in payoffs awarded for hurting opponents.

It is for the rest of us, fans, journalists, friends, foes, family, to try to make sense of Seau's death. Did those close to him miss anything that would have provided a window into his thoughts? Do we ever really know what goes through another person's mind?

Finally, athletes are being persuaded to admit they have the same disorders as the rest of the population, that it's a strength and not a weakness to go public. But what if they are not aware of their own disabilities?

Over and over the words of others are repeated: Junior Seau enjoyed life. Junior Seau was always in a great mood.

What lurked below the surface is the mystery that must be solved.

Former San Francisco 49ers offensive lineman Randy Cross, now a CBS-TV analyst, sent a warning on Twitter in the wake of Seau's death.

"Note to all my former teammates + opponents,'' tweeted the 58-year-old Cross. "Swallow macho BS + go see a Doctor, seeking help isn't weakness. It's 4 all those that love."

But maybe Seau saw no reason to visit a neurologist. Did anyone see any symptoms of a brain disorder? And until the final accounts arrive, which may not be for weeks, the only thing we can be certain of is Seau took his own life.

Our world is supposed to be one of fun and games, of escape, where the worst thing that occurs is a fumbled punt or perhaps a torn knee ligament.

One week the NFL is in thrall over the draft, a yearly highlight. Another week it is mourning the bewildering suicide of one its former greats.

Not many will give up football. It is a way of life as well as an occupation.

The first announcement of Seau's death suggested he might have been unable to adjust to the void he entered when his playing days were done. Athletes are not always prepared to deal with the end of a career.

Or, indeed, Seau, as many have proposed, could have been suffering from brain trauma, which throughout football was unmentioned if not unrecognized until the last few years.

Seau never appeared on an NFL injury report with a concussion, but that could be because he never showed symptoms.

We're ready to jump at conclusions, relying on speculation and the history of others in place of solid facts.

The only thing of which we can be certain for now is a good man is gone. Sad, so sad.