Federer, back at the Open as a fan, speaks about Sinner's 'tricky' doping case

Roger Federer thinks Jannik Sinner's doping case raises questions about whether the current top-ranked tennis player should have been allowed to continue competing until he was absolved of intentionally using an anabolic steroid he tested positive for twice in March.

"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. It's just noise that we don't want. I understand the frustration of: Has he been treated the same as others? And I think this is what it comes down to. We all trust, pretty much, at the end, he didn't do anything," Federer said Tuesday in an appearance on the "Today "show to promote a book of photos of him.

"But the inconsistency, potentially, that he didn't have to sit out while they were not 100 percent sure what was going on — I think that's the question here that needs to be answered."