Once the most expensive footballer in the world, France star Paul Pogba has sunk to a new low after being provisionally suspended for a doping violation.

Injuries and a bizarre blackmail plot involving his own brother have dominated his second spell at Juventus, and the latest revelations came just as the midfielder looked ready to get back to his best.

Italy's anti-doping authority NADO revealed on Monday that Pogba, who is still only 30, showed elevated levels of testosterone in a test taken after Juve's season-opening win at Udinese, a match in which he did not even play.

Pogba has since been a substitute in Juve's other two Serie A matches and despite picking up a thigh knock against Empoli earlier this month could well have featured in Saturday's home fixture against Lazio had he not been dealt the latest of a series of blows to his career.

The test result came soon after the release of an interview with Al Jazeera in which he said he wanted to make his critics "eat their words".

"I want to show them I'm not weak. They can talk bad about me. I will never give up," he said.

He has only started one match since returning to Juve as a free agent from Manchester United in July last year, six years after leaving the Turin giants for a then world record 105 million euros with four Italian league titles to his name.

It was a move which was supposed to regenerate his career which had gone stale in England, but he almost immediately suffered a serious knee injury in pre-season.

- 'Money changes people' -

And his initial decision to not undergo surgery in a bid to make the Qatar World Cup eventually back-fired, ending his chances of helping France defend their world title and further complicating his club campaign.

Pogba was a key figure in the 2018 triumph in Russia and scored one of France's goals in their 4-2 win over Croatia in that year's final, but he has not featured for his country since a friendly win for Les Bleus over South Africa in March last year.

From being on top of the world Pogba has slowly slipped down to the depths, ravaged by injuries and a difficult personal life which he admits has been adversely affected by the vast sums of money earned by football's top players.

"Money changes people. It can break up a family. It can create a war," he said.

"Sometimes I was just by myself thinking, 'I don't want to have money anymore. I just don't want to play anymore. I just want to be with normal people, so they will love me for me –- not for the fame, not for the money'."

Pogba speaks from bitter experience, as a month after tearing knee ligaments his brother Mathias released a video in which he threatened to reveal secrets about his superstar sibling.

French investigators were later told of how he was held at gun point by childhood friends and two hooded men armed with assault rifles, who lambasted him for not helping them out financially and demanded 13 million euros.

Pogba ended up paying 100 000 euros of the sum and the affair taught him that "the only people who can hurt are the people who are close to you".

"They're the ones who can destroy you," he told Al Jazeera.

Pogba faces an anxious wait for the result of his 'B' sample, with the spectre of a potential four-year ban hanging over a player whose life has turned into something of a nightmare.