Juventus coach Massimiliano Allegri said Saturday that Paul Pogba's ban for doping violations means football has lost an "extraordinary" talent.

Pogba was banned for four years by Italy's anti-doping tribunal on Thursday after testing positive for testosterone in the early weeks of this season, putting his playing career under threat.

"It's very sad both on a human level and for football, as we are losing an extraordinary player," Allegri told reporters ahead of Juve's Serie A match at Napoli on Sunday.

"I was lucky enough to work with him, coach him, and it's very difficult to find players like him... He's a fantastic guy."

Allegri added that he had sent Pogba, who will appeal the ban at the Court of Arbitration for Sport (CAS), a message of support but would not talk any further about an ongoing case.

France midfielder Pogba, a World Cup winner in 2018, barely featured for Juve since returning from Manchester United in 2022 due to a spate of injuries and the doping ban.

Pogba's representatives said the testosterone came from a food supplement prescribed by a doctor he consulted in the United States.

If confirmed by CAS the ban would mean that Pogba will only be able to return to playing in the 2027/28 season, by which time he will be 34.

His positive doping test came as he was trying to put behind him a difficult first season back at Juve, in which he made just 10 appearances, while also missing France's unsuccessful defence of the World Cup in Qatar due to injury.

He made two substitute appearances for Juventus at the start of this campaign before being suspended following his initial adverse sample which was confirmed as positive in early October.

Meanwhile an investigation is ongoing in France into an extortion attempt against him in March 2022, in which Pogba's older brother Mathias is one of the suspects along with childhood friends of the family.

Two intruders allegedly broke into Pogba's home in the Paris suburbs and held him against his will, demanding 13 million euros ($14.1 million at today's rates).