Roger Federer has questioned why Jannik Sinner was not provisionally suspended after the Italian world number one failed two drugs tests earlier in the year.

In March, Sinner twice tested positive for clostebol, an anabolic steroid. He claimed the steroid had entered his system through a massage from his physiotherapist, and was eventually cleared of any wrongdoing by an independent tribunal in August.

There were claims that Sinner was receiving preferential treatment, with fellow player Denis Shapovalov writing on social media that there were “different rules for different players”. More recently, Sinner admitted that he got a frosty reception in the locker room at the US Open.

Federer weighed in on the debate when speaking to NBC, saying: “I understand the frustration of, ‘Has he been treated the same as others?’ And I think this is where it comes down to”.

“I think we all trust pretty much that Jannik didn’t do anything, but the inconsistency potentially that he didn’t have to sit out while they weren’t 100 per cent sure what was going on, I think that’s the question that needs to be answered.

“It’s not something we want to see in our sport — this type of news — regardless if he did something or not, or any player did,” Federer said.

“It’s just noise that we don’t want. I understand it’s a tricky situation. It’s the nightmare of every athlete and team to have these allegations and these problems.

“And it lives with you. Every morning when you wake up, you think, ‘Is somebody at the door coming to test me?’ So it’s really difficult,” added the former world number one.

Before the US Open, Sinner cut ties with his physio and fitness coach, and he has since progressed to the quarter-finals, where he will face Daniil Medvedev on 4 September.

In other news, Flushing Meadows will see its first American men’s finalist since 2006, after Frances Tiafoe and Taylor Fritz advanced in their respective quarter-finals to set up an all-American semi-final on Friday, 6 September.