Autumn ushers in the NBA season proper. Gliding somewhere on the gleaming hardwood floors and through all the millionaire ball players is the ghost of Lenny Cooke.

Or, more accurately, the ghost of Lenny Cooke circa 1999, when he was an incalculably promising 17-year-old basketball prodigy, ranked above LeBron James, Carmelo Anthony and Amar’e Stoudemire as the best high school player in the league. Sport and maybe Hollywood are the only worlds in which Fitzgerald’s wistful observation about second acts and American lives is strictly and savagely and constantly true. You get one chance only.

The year's new season has been dominated by the return of LeBron James to ailing, perennially unfashionable Cleveland, the local city he spurned for Miami only to see the light. His decision was both honourable and smart: if and when he wins championships in Cleveland, they will be become definitive moments in the game and his real legacy. And it gives the most slickly marketed sport in the business a plot line to rival House of Cards.

The advance art work has been cinematic, with Bray’s own Hozier providing the soundtrack for a sustained two-minute aria/advert for headphones, in which James returns to the fabled St Vincent gymnasium in Akron to work out and step back in time.

It isn’t all that long ago that all of it was in front of James. You can be certain he still retains vivid recollection of the best of his adolescent peers, in particular Lenny Cooke, the New York phenomenon who was regarded as dead cert NBA material.

Hoop legend

For years Cooke was nothing more than a vague, urban myth: hoop geeks who had played close attention to the best emerging players in the ’90s would have recalled the superlative reports emanating from his exploits in Manhattan and, later, New Jersey. He had all but disappeared until Joshua and Rafe Safdie, brothers and film-makers, spliced together footage of an abandoned film project on Cooke as rising star and the 32-year-old he is today.

In the opening sequence of Lenny Cooke, the subject is at the epicentre of a basketball gym crowded with the best young players in the country, who are starkly presented with the statistical chances of making it to the NBA. They're told there were 348 players on NBA rosters on the opening night of the 2000 season. The US population is 281 million. "So you literally have to be one in a million."

Cooke didn’t doubt that he was, and it wasn’t a question of if he’d make the big league, but about when he should declare and how high a draft pick he would be. In 2001, Kwame James Brown, a 6’11” player from Georgia had thrown the traditional college path to the NBA into chaos by declaring straight from school and duly been chosen No 1 by the Washington Wizards.

There is footage of Cooke watching that year’s draft, lounging in the television room of his guardian and shaking his head at the absurdity of Brown’s sudden elevation. “Instant millionaire,” he snorts, before warning his friends about what the young star faces: “82 games a season. On the road! Away from your friends and family. That shit is hard.”

Dollars and sense

It wasn’t as if the prodigies weren’t warned about the illusion of limitless NBA wealth: in another presentation, the prodigies are given a financial breakdown of best-case scenarios. Brown’s contract earned him a guaranteed $4 million a year for three years. The sixth pick earned $2 million. On a blackboard, a coach breaks down a million dollars a year into monthly earnings after taxes and rent and cars and insurances and cars for family members and agents fees. The superstar is left with $10,000 a month. “Better not piss that 10 away or you’re really in trouble,” the coach tells them.

These are 17-year-olds whose minds are swimming with the profile their brilliance at basketball gives them, with advice on every corner, college recruiters trying to persuade them to sign here and there, trying to keep on top of schoolwork so they remain eligible to play and, in many cases, trying to make good on the only chance that they or their family has to make it out of extreme poverty.

The footage of Cooke’s match-up against LeBron James is unforgettable, containing as it does a subtle but noticeable shift in the trajectory of basketball. Coming into the ABCD camp that day, James, younger by two years, was still the upstart to Cooke’s star, but you can see perceptions shift over the course of their game. Even in the interview, it’s clear that James and Carmelo Anthony are already a bit harder and clearer in their worldview than Cooke, who is both sweet-natured and full of braggadocio.

The most storied coaches in the game are all in the stands, and although Cooke is sublimely good and smooth, James plays with unremitting assurance and executes a running-jumper to win their encounter.

For the first time, you can see a flitter of doubt flash across Cooke’s face. Until that day, James was a vague rival whom Cooke assumed he would be meeting many times in their gilded futures. Now, James had out-scored him 24-9 and won the match.

They would never play against each other again. By that night, Cooke had dropped from No 1 to No 3 in the country. Incredibly, it was the beginning of the end for him: a messed-up final year in school left him playing pick-up games, and his decision to declare for the NBA draft made him inadmissible for college.

Within a year, the vogue for raw high-school prodigies was over, and no team thought Cooke worth the gamble. He tried to play his way back in through obscure regional leagues and seasons in China and the Philippines, but his ship had sailed.

When we next see Cooke, he is celebrating his 30th birthday, considerably heavier, pretty tipsy, singing Mario's Let Me Be the One to his girl and having boozy what-if conversations with his friends.

Briefly back

Lenny Cooke

was backed by Joakim Noah, a contemporary who is now an All-Star centre with the Chicago Bulls and clearly fond of the subject. When the Bulls play the Knicks at Madison Square Garden, Cooke is there afterwards to greet Noah and Carmelo Anthony – “He was the only one to wear Jordans at an Adidas camp” Anthony recalls –and for a few minutes, they are equals again.

The reason millions of people tune in to watch LeBron James is because what he can do is unfathomable. But what if you were one of the few with the physique and skill and speed to make whatever James had not just fathomable but conquerable?

Lenny Cooke had all that, and it was like sand through his fingers.