Novak Djokovic understands why some tennis players question whether there is a double standard in their sport after world number one Jannik Sinner was not banned despite two positive steroid tests, and agrees there is “a lack of consistency”.

Sinner tested positive for anabolic steroids twice in March, but the International Tennis Integrity Agency concluded that the banned performance-enhancing drug entered his body inadvertently during a massage by his physiotherapist. Last week, a court acquitted him of any guilt or negligence.

The decision was announced on Tuesday, less than a week before Australian Open champion Sinner begins the US Open as the top seed. Djokovic, who won the tournament last year to win his 24th Grand Slam men’s singles title, is the No. 2 seed.

“I understand that players are frustrated with a lack of consistency,” Djokovic said on Saturday. “From what I understood, his case was basically resolved from the moment this was announced.”

Some players commented on the news on social media, wondering if Sinner was lucky because he has the status of one of the best players in the sport.

“We see a lack of standardized and clear protocols. I can understand the feelings of many players who wonder if they are being treated equally,” Djokovic said.

Djokovic said he was a co-founder of the Professional Tennis Players Association and advocates on behalf of the players for clear and fair protocols and a standardized approach to cases.

“Many players … have had similar or more or less the same cases that did not lead to the same result,” Djokovic said, “and now the question is whether it is a question of finances – whether a player can afford to pay a significant amount of money to a law firm that will then represent his case more efficiently.”

Carlos Alcaraz, the 2022 US Open champion, said Sinner’s case was a delicate matter.

“I think there’s something behind it that a lot of people don’t know. I don’t even know. Ultimately, it’s something that’s hard to talk about,” Alcaraz said.

“Ultimately, his test was positive, but there must be a reason that allowed him to continue playing that we don’t know. So I can’t say much about it.”

“He was declared innocent and so we have Jannik in the tournament. So there is not much to discuss and I am not in a position to add anything.”

Sinner repeatedly protested his innocence and said he was able to continue playing because his team quickly identified the source of the contamination.

He tested positive for the steroid clostebol after his physiotherapist Giacomo Naldi applied an over-the-counter spray to a cut on Sinner’s hand before treating him.

The spray was given to Naldi by coach Umberto Ferrara. He fired Naldi and Ferrara.

“The reason I could have played (after the positive tests) was because we knew where the substance was and how it got into my body,” Sinner said Friday.

“It is very important to go through this process, to inform them about it, and they understood it immediately.

“Anyone who knows me well knows that I have never done anything and would never do anything that violates the rules.”

He stressed: “Every player who tests positive has to go through the same process. There is no shortcut, there is no different treatment, it is the same process for everyone.”