Jannik Sinner Rehires Fitness Trainer Umberto Ferrara

ATP World No. 1 Jannik Sinner has rehired fitness trainer Umberto Ferrara. The two had worked together for several years before Ferrara and physiotherapist Giacomo Naldi were let go following Sinner's positive test for Clostebol.

While Ferrara is back on Sinner's coaching staff, Naldi will not be returning. Ferrara purchased the Trofodermin, an over-the-counter spray, containing Clostebol, in February 2024. Then, physio Giacomo Naldi used the spray on his own hand, inadvertently contaminating Sinner.

Sinner's positive test threatened to derail his career, but after a lengthy legal battle, the Italian superstar grudgingly accepted a three-month ban earlier this year.

Jannik Sinner has re-hired fitness trainer Umberto Ferrara.

Sinner previously parted with Ferrara for his part in the clostebol case: Ferrara purchased the spray, containing clostebol, which physio Giacomo Naldi then used on his own hand and inadvertently contaminated Sinner.
— James Gray (@jamesgraysport) July 23, 2025

According to Federica Cocchi of Gazzetta, the new hire is effective immediately. Ferrara will resume working with Sinner during training sessions in Monte Carlo this week.

Sinner's management put out the following statement, "Jannik Sinner has reappointed Umberto Ferrara as his fitness coach with immediate effect. 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 U.S. Open.

"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."

On ESPN a few months ago Darren Cahill confirmed that Umberto Ferrara was a highly experienced and qualified fitness coach and a pharmacist and that he was in charge of all of Sinners anti doping controls.

Cahill said had no knowledge why Ferrara had a banned substance with him. pic.twitter.com/hVG0WucgGx
— Pavvy G (@pavyg) July 23, 2025

Tennis fans will remember that Sinner fired athletic trainer Marco Panichi and physiotherapist Ulises Badio just three days before Wimbledon (which he would eventually go on to defeat Carlos Alcaraz and win his fourth Grand Slam title).

After readjusting his staff multiple times, Sinner looks for stability before his coach, Darren Cahill, takes a step back following the conclusion of the 2025 ATP season.

Sinner has not competed since he won Wimbledon earlier this month. He is currently 26-3 with two singles titles. Stay locked into Sports Illustrated's Serve On SI for all of your tennis news from the court and beyond.

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