NEW YORK (AP) — Jannik Sinner fired his fitness trainer and physiotherapist because of his two positive steroid tests in March and said Friday, Aug. 23, at his pre-U.S. Open news conference — his first public comments on the matter — that he knew he was innocent but worried what the case’s outcome would be until finding out he wouldn’t be suspended.

Sinner’s fitness trainer, Umberto Ferrara, and his physiotherapist, Giacomo Naldi, have been at the 23-year-old Italian’s side during his rise over the past two years, which included his first Grand Slam title at the Australian Open in January and ascension to the No. 1 ranking in June.

“I’m not feeling that confident to continue with them,” Sinner said. “Now I just need some clean air.”

The International Tennis Integrity Agency (ITIA) announced this week that Sinner failed two drug tests — one during a tournament in Indian Wells, California, and one eight days later — but that it was determined the banned anabolic steroid Clostebol entered his system unintentionally through a massage from Naldi.

“Obviously it has been a very tough moment for me and my team,” Sinner said. “It still is, because it’s quite fresh.”

Play begins Monday at Flushing Meadows. Sinner is the top-seeded man and is scheduled to meet first-round opponent Mackie McDonald, an American ranked 140th, on Tuesday.

“Of course it’s not ideal before a Grand Slam,” Sinner said with a chuckle about the timing of the news. “But in my mind, I know that I haven’t done anything wrong. I had to play, already, (for) months with this in my head, but just (was reminding) myself that I haven’t done really anything wrong. I always respect these rules — and I always will respect these rules — of anti-doping.”

He is considered one of the leaders of the next group of male tennis stars who will succeed the Big Three of Roger Federer, Rafael Nadal and Novak Djokovic. Sinner is 48-5 with a tour-leading five titles in 2024 and tuned up for the U.S. Open by winning the hard-court Cincinnati Open on Monday.

“He’s an incredible player, and, you know, (governing) bodies made a decision. They went and did that; he’s cleared to play. That’s pretty much what I have to say about it,” said Frances Tiafoe, the American who lost to Sinner in the final at Cincinnati. “All the best to him in the U.S. Open.”

Sinner’s defense was that Ferrara purchased an over-the-counter spray that contained Clostebol in Italy, then gave it to Naldi, who used it on a cut finger. Sinner said Naldi then gave him a massage.

The investigation found that Sinner had a trace amount of the steroid in his system, a point he illustrated Friday by using eight fingers to count out the number of zeroes before the “1” in the amount: .000000001"

Asked whether he thinks the episode will affect his reputation, Sinner said: “We will see now — now, moving forward. Because this, I can’t really control.”

He also called the outcome “a relief.”

“Of course I was worried,” Sinner said, “because it was the first time for me — and hopefully the last time that I am in this situation, position.”