Men's tennis number one Jannik Sinner withdrew from the Paris Olympics on Wednesday, days before it begins, after falling ill with tonsillitis.

The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.

"After seeing my doctors on Tuesday and waiting an extra day to give myself some more time to see if my condition would improve, things unfortunately got worse," Sinner, 22, said in a statement.

"I was looking forward to competing with my teammates and the rest of the Italian team, but for now that will have to wait.

"As advised by my medical team, I will now take some time to rest and recover to full health. I'd like to wish the whole team Italia the best for this important event and hope to be back stronger in the future."

Sinner said the Olympics had been "one of my main goals for this season" and was due to play in the men's singles and the doubles with Lorenzo Musetti.

Wimbledon semi-finalist Musetti will now have to play in the men's doubles tournament with either Luciano Darderi or Matteo Arnaldi.

Italian media reported that Andrea Vavassori, ranked 207 in the world, will replace Sinner in the men's singles.

Sinner dropping out deprives Italy of a great shot at a medal.

He has long been the great hope of Italian tennis and after finishing runner-up to Novak Djokovic at the ATP Finals in November last year, he has moved up a level.

Sinner won his first Grand Slam at the Australian Open at the start of this year and then became the first Italian to top the world rankings after his recent run to the semi-finals at the French Open.

He has also won three other tournaments this year, including his second Masters 1000 crown in Miami.

Sinner withdrew from the Madrid Open before the quarter-finals with a hip injury and missed the tournament in Rome in the run-up to Roland Garros, where the Olympic tennis will be played between July 27 and August 4.

He needed a lengthy medical timeout after feeling dizzy and appearing to almost lose his balance during his quarter-final defeat to Daniil Medvedev at Wimbledon.