Last year, tennis was rocked by two separate doping cases featuring two of the sport's biggest names, Jannik Sinner and Iga Swiatek. On Saturday, after a long saga, it was announced that Sinner would accept a three-month ban. Swiatek, meanwhile, had accepted a one-month suspension in November.
Here's everything we know about both situations:
What substance did Jannik Sinner test positive for?
On March 10, 2024, during the BNP Paribas Open in Indian Wells, California, and again out of competition on March 18, Sinner tested positive for prohibited substance clostebol, a synthetic anabolic-androgenic steroid (AAS), via urine samples. In both tests, "low levels" of the drug were detected, less than one billionth of a gram. The March 10 sample contained 86 picograms/liter while the March 18 sample contained 76pg/liter.
This drug, which in the United States is designated as a Schedule III controlled substance, is often used for ophthalmological and dermatological treatments. It is the same drug that San Diego Padres star Fernando Tatis Jr. was found to have taken and subsequently suspended by MLB for 80 games.
What explanation did Sinner give for the positive tests?
Sinner said the substance entered his system unintentionally as a result of a massage from his physiotherapist, Giacomo Naldi, who had been applying over-the-counter spray Trofodermin, containing clostebol, to his own skin to treat a small wound. The medication was purchased by Sinner's fitness coach, Umberto Ferrara, in Italy where treatments containing clostebol are readily available over the counter.
Sinner claimed Naldi used the medication for a nine-day period and treated Sinner without gloves.
What rulings have been made in the Sinner case?
Sinner was provisionally suspended from tennis on April 4 after those test result findings for violating Article 2.1 and Article 2.2 of the Tennis Anti-Doping Programme (TADP). He then lodged an appeal to the International Tennis Integrity Agency (ITIA) -- the sport's worldwide anti-doping agency -- and was allowed to continue playing. He lost the $325,000 and 400 points that he had earned at the tournament in Indian Wells.
On Aug. 15, an independent tribunal commissioned by the ITIA and arbitrated by Sport Resolutions absolved Sinner of his doping charges. At the hearing, three scientific experts accepted the world No. 1's claim and found it was a credible explanation that he had been inadvertently contaminated with the substance via the physiotherapy treatment. The ITIA pointed to Article 10.5 of the Tennis Anti-Doping Programme, agreeing Sinner bore "no fault or negligence" in testing positive twice, given the treatment was administered by his physiotherapist. Sinner was cleared of any wrongdoing and avoided a doping ban.
"Even if the administration had been intentional, the minute amounts likely to have been administered would not have had any relevant doping, or performance enhancing, effect upon the player," said Professor David Cowan, a member of the ITIA tribunal for its final ruling on the case.
Then, on Aug. 20, on the eve of the US Open, the case became public knowledge. Shortly after, Sinner parted ways with both Naldi and Ferrara. "Now, because of these mistakes, I'm not feeling that confident to continue with them," Sinner said.
"I will continue to do everything I can to ensure I continue to comply with the ITIA's anti-doping programme," said Sinner, following his exoneration. "I have a team around me that are meticulous in their own compliance. I know that I haven't done anything wrong. I always respect these rules, and I always will respect these rules of anti-doping."
On Sept. 26, the ITIA's decision was appealed by the World Anti-Doping Agency (WADA). "It is WADA's view that the finding of 'no fault or negligence' was not correct under the applicable rules," WADA said in a statement.
In December, WADA director general Olivier Niggli told AFP, "It was considered in the decision that there was no fault on the part of Sinner. Our position is that there is still a responsibility of the athlete in relation to his entourage, so it is this legal point that will be debated [before CAS].
"We do not dispute the fact that it could have been a contamination. But we believe that the application of the rules does not correspond to the case law."
On Feb. 15, it was announced that Sinner had accepted a three-month ban in a settlement with WADA. The timing means that he won't miss any Grand Slam tournaments since the next major, the French Open, starts May 25.
"This case had been hanging over me now for nearly a year and the process still had a long time to run with a decision maybe only at the end of the year," Sinner said in a statement. "I have always accepted that I am responsible for my team and realize WADA's strict rules are an important protection for the sport I love. On that basis I have accepted WADA's offer to resolve these proceedings on the basis of a three-month sanction."
How did players react to the three-month ban for Sinner?
Novak Djokovic, the 24-time major champion, said a majority of tennis players have lost faith in the anti-doping authorities following Sinner's three-month ban.
"It's not a good image for our sport, that's for sure," Djokovic said. "There's a majority of the players that I've talked to in the locker room, not just in the last few days, but also last few months, that are not happy with the way this whole process [for Sinner] has been handled.
"A majority of the players don't feel that it's fair. A majority of the players feel like there is favoritism happening. It appears that you can almost affect the outcome if you are a top player, if you have access to the top lawyers and whatnot."
No. 5-ranked Jessica Pegula shared her thoughts on Sunday, at a press conference ahead of the Dubai Duty Free Tennis Championships. "Whether you think he did or you don't, or whatever side you're on, the process just seems to be completely not a process. It seems to just be whatever decisions and factors they take into consideration, and they just make up their own ruling. I don't really understand how that's fair for athletes, how it's fair for players when there's just so much inconsistency and you have no idea."
British tennis player Liam Brody also weighed in. "I do think a lot has been put into when the ban would take place, to impact Jannik's career as little as possible," Broady told BBC Sport."
Australian player Nick Kyrgios called it a "sad day for tennis" in a post on X, while three-time major champion Stan Wawrinka posted: "I don't believe in a clean sport anymore ..."
Daniil Medvedev, in a press conference after losing in the Open 13 semifinals in Marseille, said, "I hope everyone can discuss with WADA and defend themselves like Jannik Sinner from now on."
Former British No. 1 Tim Henman told Sky Sports, "When I read the statement this morning, it just seems a little bit too convenient. Obviously having just won the Australian Open, to miss three months of the tour and therefore to be eligible to play at Roland Garros, the timing couldn't have been any better for Sinner, but I still think it leaves a pretty sour taste for the sport."
What substance did Iga Swiatek test positive for?
On Aug. 12, Swiatek tested positive in an out-of-competition sample for low levels of the prohibited substance trimetazidine, a non-specified anti-anginal medicine often used to treat heart-related conditions.
Trimetazidine is not approved by the FDA for clinical use in the United States.
What explanation did Swiatek give for the positive test?
Swiatek said she discovered that a non-prescription melatonin medicine manufactured and regulated in her native Poland contained the substance. She had been taking the sleep medication "for jet lag and sleep issues," and did not hold a valid Therapeutic Use Exemption (TUE) prior to her positive test.
What ruling has been made in the Swiatek case?
The ITIA sent Swiatek a pre-charge notice of an anti-doping rule violation immediately after testing positive for the banned substance. Findings for such non-specified substances carry a mandatory provisional suspension, which was subsequently handed down by the ITIA on Sept. 12.
On Sept. 22, Swiatek appealed the provisional suspension. Days later, she learned her sleep medication was responsible for her contamination and informed the independent tribunal chair. The contamination was confirmed by the independent and WADA-accredited Sports Medicine Research & Testing Laboratory in Utah.
"Once the source had been established, it became clear that this was a highly unusual instance of a contaminated product, which in Poland is a regulated medicine," said ITIA CEO Karen Moorehouse. "However, the product does not have the same designation globally, and the fact that a product is a regulated medicine in one country cannot of itself be sufficient to avoid any level of fault. Taking into account the nature of the medication, and all the circumstances, it does place that fault at the lowest end of the scale."
The independent tribunal chair lifted the provisional suspension on Oct. 4. Swiatek accepted a one-month sanction and completed her period of ineligibility on Dec. 4, after having returned to the court for the WTA Finals and Billie Jean King Cup finals.
"First three weeks were pretty chaotic. There was no way to have any answers to the questions," said Swiatek. "We just focused on finding the source. But I got to say it wasn't easy. It was probably like the worst time in my life and the fact that I had no control over this whole situation and I had no chance to avoid it, it made it even worse."
Does this mean the Swiatek case is now closed?
Yes. On Jan. 20, a little over an hour after Swaitek had book her spot in the Australian Open quarterfinals, WADA announced it would not be appealing her case.
Prior to the announcement, Swiatek had stated she was confident there would be no appeal.
"I gave every possible evidence and there is not much, honestly, more to do. There is no point to do an appeal in our opinion," said Swiatek at a press conference at the United Cup. "But, you know, I guess overall, this whole process was pretty abstract sometimes and hard to understand from a point of view where you don't think about the law and everything.
"I can say from the processes that I went through and how they treated me from the beginning, that it seemed fair for me. I managed to give the source [of the contamination] pretty quickly. That's why the case closed, pretty quickly. I try to just go on with my life and focus on different things, focus on preparing for the season and on tennis, because this is the best thing you can do after a case like that."