LockerRoom: In his introduction to FX Toole's unfinished novel Pound for Pound, James Ellroy notes that "boxing tempts writers . . . it taunts them with the knowledge that they do not and will not ever belong". He's right.

Anyone who has ever covered a prize fight in Vegas or Madison Square Garden has done so as an anthropologist, sending back dispatches from a world of wonder and fear. Boxing attracts the scribblers with the tough-guy styles, the Mailers, the Schulbergs and the Hemingways, and it attracts those looking for some deeper metaphor, Joyce Carol Oates, Thomas Hauser, David Remnick. It repels and fascinates.

Sportswriting is a tame business, and the worst we expose ourselves to in terms of injury is paper cuts and liver damage. The only time I have been frightened was covering a Mike Tyson fight in the MGM Grand in the 1990s. Tyson gave off such an air of menace even then, past his heyday, that the main consolation in being exposed to him was that the fawning retinue of chisellers and grifters who surrounded him would most likely kill you before Mike got near you with his wrecking-ball mitts.

One day though, approaching the lifts in the MGM with a couple of game chorus girls and a bucket of cash cleared from an all-night session of Texas hold 'em, I was surprised to be shoved out of the way by the point man in Tyson's retinue. Naturally I was delighted to oblige by humbly squeezing myself back against the wall and pushing the chorus girls out as human sacrifices.

Not so happy was a small Jewish man with a whiny New York accent who suddenly materialised and began berating Tyson to his face. You shouldn't be in a family hotel, he told the baddest man othe planet, you're an animal and a rapist, you're a criminal and you shouldn't be here.

What an incredible scene. The man had the physique of Woody Allen. With back-up I would have fancied my own chances against him. The world, entourage and all, just stopped and waited to see what would happen. The space was confined, and it genuinely felt as if somebody had provoked a lunatic with a firearm. If Tyson went off in the elevator lobby of the MGM Grand there was going to be screaming (mine) and blood (little Jewish guy at whom I am pointing finger) and stampeding (me again). Hectoring Tyson like that was the bravest thing I've seen - and Tyson's reaction was among the saddest.

This look of cold, resigned hurt crossed his face, and he stared at the ground and shuffled on. I never thought it was possible to feel sorry for somebody as wilfully out of control as Tyson was back then, but that morning he looked whipped, he looked like he knew what life held for him. He was paying dues, and he'd be paying them for a long time to come.

He was back in Las Vegas a few weeks ago. Great boxers do Vegas twice. Once on the way up, as golden warriors, and once on the way down, as freak shows. Mike Tyson was in a bar in the Aladdin Hotel, "working out" in a makeshift ring for the benefit of a couple of hundred boozed-up low-rollers. Tyson lumbered around, an old, worn-out bear of a man, and threw some half-hearted punches at his latest trainer, Jeff Fenech. People took pics with their cell phones and texted them about the place.

Even those of us who wrote in reproof and rebuke over the years of Tyson could take no pleasure in seeing a man so ill-used by the world that he has been left without his dignity. Whatever his appetites and his failings, Tyson was ruthlessly clipped and fleeced by those around him. The $300 million he earned from the fight game is gone. More than that, in fact: he owes incalculable millions. The little bucketful he got from degrading himself in the Aladdin was being used to keep the wolf from the door a small bit longer.

This week, inevitably, he was giving a half-hearted press conference announcing that not just was he back training last week, but that he is stepping back into the ring to give four exhibition bouts over the next few months. He'll be back fighting for the first time since his humiliating loss to the tomato can Kevin McBride just over a year ago. I know Kevin is our tomato can, but still. That was long past the point where it should have all ended.

The words coming out are drenched in pathos. "I truly hate fighting," he says, "I've got a bad taste in my mouth. I'm useless to society. I don't think I'm worthy of the people who come out to see me, but they do."

Of course behind every exploited boxer there is a classy promoter with a heart of gold. Tyson has found his way into the arms of one Sterling McPherson, and McPherson, it is reported, is attempting to add his own touch of class to the coming bill by luring former lightweight champion Paul Spadafora to provide one of the supporting acts. Luckily, Spadafora was paroled earlier this year. He's spent some time away after shooting his fiancee.

The trainer Eddie Futch, who might have saved Tyson if the moneygrubbers hadn't kept him at strong-arm's-length, once quoted the essayist Elbert Hubbard. The lines seem apposite for Tyson now.

"Habit writes itself on your face. To have a beautiful old age you must live a beautiful youth. I am today what I am because I was yesterday what I was."

Tyson grows old, past 40 now, and runs out of chances. He lives with a Maori tattoo across one side of his face and with his strength deserting him only slightly more slowly than his friends have. His dignity left town long ago.

It used to be easier to judge Mike Tyson. Years ago he was Rapist. Lunatic. Baddest Man on the Planet. You could say to yourself that if you'd lived the life he had endured that perhaps you would have been no different. Perhaps. At 40, though, Tyson is at the bottom, and his melancholy and his humility make him a compelling figure.

"I think if I don't get out of these financial quagmires," he said last week, "there's a possibility I may have to be a punching bag for somebody. I don't want to do that anymore. Everybody's saying, 'Mike, make a comeback'. I'm not going to do that."

The history of boxing, the history of Tyson, suggests there is a promoter out there willing to make Tyson an offer to step into a ring and put his life in danger.

Tyson has been for a long walk in the dark woods and there are many miles to go yet. Forty. Half a lifetime, and still no clearing.

For the second half of his ruined, empty life we might just root for him and what's best for him.