Sinner reappoints fitness coach Ferrara

Jannik Sinner (right) and Umberto Ferrara (left) stopped working together last August

World number one Jannik Sinner has reappointed fitness coach Umberto Ferrara, with whom he parted ways following the investigation into his positive tests for a banned substance.

Ferrara and physiotherapist Giacomo Naldi left the Italian's team last August, five months after Sinner returned two positive tests for clostebol.

"Umberto has played an important role in Jannik's development to date, and his return reflects a renewed focus on continuity and performance at the highest level," a statement from Sinner's team read.

"The decision has been made in alignment with Jannik's management team as part of ongoing preparations for upcoming tournaments, including the Cincinnati Open and US Open."

Sinner was cleared by an independent tribunal of any wrongdoing last August but the World Anti-Doping Agency (Wada) appealed against the panel's ruling that he "bore no fault or negligence".

The 23-year-old accepted a three-month ban in February after reaching a settlement with Wada.

Wada said it accepted that Sinner did not intend to cheat but bore responsibility for "the entourage's negligence".

Sinner said the substance clostebol, which can increase muscle mass, entered his system when Naldi applied an over-the-counter spray to treat a cut on his hand.

Ferrara said he provided the spray to Naldi for personal use and warned him not to use it on Sinner.

After the departures of Ferrara and Naldi, Sinner appointed fitness coach Marco Panichi and physiotherapist Ulises Badio in September.

However, he parted ways with them shortly before this year's Wimbledon.

Sinner made his return at the Italian Open in May.

He lost the French Open final to Carlos Alcaraz in a five-set thriller in June, before beating him in the Wimbledon final this month to win his fourth Grand Slam.

'Sinner feels Ferrara has learned from mistakes' - analysis

Sources close to Sinner told BBC Sport that he feels Ferrara, who has been working with Matteo Berrettini, has learned from his mistakes.

Ferrara has a degree in pharmaceutical technology and was specifically chosen by Sinner previously to advise him on anti-doping issues.

The initial independent tribunal found Ferrara provided the spray to Naldi with a warning - but in the knowledge it contained a prohibited substance and the physio would be treating Sinner with his bare hands.

As part of his defence - outlined in the tribunal's decision last August - Sinner's legal team argued that it was "not the gravity of Mr Ferrara's mistake that the player is responsible for but his choice in appointing Mr Ferrara in the first place and his supervision of him".

In reaching a settlement with Sinner, Wada said Sinner tested positive as a result of the "negligence of members of his entourage" and, under its code, this is a negligence an athlete bears responsibility for.

BBC Sport has asked Sinner's representatives whether Ferrara will once again have responsibility for anti-doping matters.

But Sinner believes he can trust Ferrara again and - importantly for a player chasing the biggest prizes - feels the reintroduction of a familiar face is essential to maintaining his place at the top of the game.