How tennis doping rules on whereabouts and contamination will change under 2027 WADA rules New York Times (Online) Amelie Claydon Tennis players who argue that they have tested positive for a banned substance due to contamination could have more recourse — and could receive reduced suspensions — under anti-doping codes taking effect in January 2027, which will also affect whereabouts rules that govern how and when players are tested. The World Anti-Doping Agency (WADA) has expanded the circumstances in which athletes can qualify for reduced sanctions, replacing its definition of a “contaminated product” with the broader term, “contaminated source”. The change also broadens the possible arguments that athletes can make if they defend themselves against a positive test on the basis of contamination. Those changes will apply to all sports led by WADA's anti-doping code. Tennis, specifically, will also change its whereabouts rules. Players have to provide a one-hour window for testing each day of the year, updating their whereabouts as they move around the world. They can also be tested outside of their allotted hour at any time. 2023 Wimbledon champion Markéta Vondroušová is currently serving a four-year suspension in part because she believed she could only be tested during her allotted hour. She is set to appeal the ban at the Court of Arbitration for Sport. From 2027, players in the Registered Testing Pool, which currently includes but is not limited to the top 100 singles and doubles players on both tours, will also have to provide a 60-minute slot when they are at tournaments. Tennis was previously exempt to this requirement, but changes to WADA's code mean the sport now has to follow it. After consultation with WADA, the ITIA said it will reduce the number of players in the current RTP. Players no longer selected for it will be part of a broader testing group that is not subject to the new requirement. Random testing will remain, but for that broader group whereabouts will be determined by accommodations and training information. Those players will no longer have to provide whereabouts slots every day. The changes follow high-profile tennis anti-doping cases involving four-time Grand Slam champion Jannik Sinner , six-time Grand Slam champion Iga Świątek and British player Tara Moore , all of which hinged on the definition and consequences of contamination. Under the existing code, a contaminated product is defined as one containing a banned substance that is not disclosed on its label or through a reasonable internet search. The 2027 code defines a contaminated source as “an unforeseeable source of a Prohibited Substance”, explicitly including contaminated meat, food and drink, physical contact with another person and objects that players have handled. Players must still establish the source of contamination and demonstrate no significant fault or negligence, with possible sanctions ranging from a reprimand without suspension to a two-year ban. Sinner, the world No. 1 who is out with a right knee injury for the rest of this year, tested positive for the anabolic steroid clostebol twice in March 2024. In his defense, the Italian said that his physiotherapist used a spray containing the substance to treat a cut on his own hand before massaging Sinner, which led to the clostebol entering his bloodstream through cuts and sores on his skin caused by psoriasiform dermatitis. An independent tribunal initially found Sinner bore no fault or negligence, but he accepted a three-month suspension in February 2025 after WADA appealed against the ruling, with the agency arguing that the player had to be held responsible for his team's negligence. His case did not qualify under the existing contaminated-product provision because the substance was transferred through physical contact, which is expressly covered by the new definition. Świątek accepted a one-month suspension in November 2024 after she tested positive for trimetazidine, a medication that increases bloodflow to the heart and lungs. Świątek argued that the positive test came from contaminated melatonin medication that she had taken to help with sleep and jet lag. To establish the source, her team provided purchase receipts, medical records and laboratory results before sending her opened medication container and a sealed container from the same batch for independent analysis at a WADA-accredited laboratory in Salt Lake City. The laboratory detected trimetazidine in tablets from both containers, with concentrations consistent with her positive urine sample. Like Sinner, British player Moore was initially cleared by an independent tribunal after testing positive for boldenone and nandrolone at a tournament in Colombia, with the panel accepting in December 2023 that contaminated meat explained both substances. However, the Court of Arbitration for Sport overturned the ruling on nandrolone in July 2025, imposing a four-year ban on Moore after finding that eating contaminated meat could not explain the concentration detected in her sample. Moore's urine contained 105 nanograms per milliliter of the nandrolone metabolite 19-norandrosterone — more than seven times the 15 ng/mL reporting threshold. The CAS majority considered the explanation involving two steroids in contaminated meat highly unlikely, illustrating why the requirement to establish the source remains significant despite the broader new rules. The ITIA also announced that existing restrictions on betting and its promotion will explicitly cover prediction markets, fantasy sports competitions and sweepstakes involving money and tennis . The clarification follows commercial agreements between the ATP Tour and Polymarket, and the U.S. Open and Kalshi, both of which were announced earlier this year. Analysis from senior tennis writer Matthew Futterman The thing most tennis players hate about the anti-doping process is getting woken up at 5 a.m. with a knock on the door. The thing they hate second-most is the all the cyber-paperwork they have to fill out properly every day. If they mess up, there can be massive consequences. Athletes have to say that they are going to be somewhere for 60 minutes a day, every day, for anti-doping testing. If their their plans change at the last minute and they end up somewhere else without updating their whereabouts, they risk a missed test. Three missed tests within an 12-month period means a two-year suspension. Previously, tennis players have enjoyed an exemption from specifying that hour when they were in the middle of tournaments. The thinking was they were easy to find then. That exemption goes away on January 1, but the rule-change comes with some relief for all but about 50 players. The ITIA is shrinking its Registered Testing Pool from about 250 players to around 50 — roughly the top 20 men and women in singles and then a handful of others who are there because they might be coming back from a suspension or some other reason. The pool will carry the burden of specifying where they will be for an hour each day regardless of whether they are playing in a tournament. Everyone else will be able to stop doing that. Just like the top tier of players, everyone else will still have to specify the following each day: home address, email address and phone number; an address for overnight accommodations; regular activities such as training, work, and school; the locations and the times of these activities; their competition schedules and their locations. That's a big relief, especially for athletes in a sport where schedules can change quickly, depending on a win or a loss or the weather, or canceled flights. But in the case of the new, smaller RTP, it's yet another headache. In the middle of a competition, with schedules available everywhere with a few taps of any phone or keyboard, forcing players to offer up their whereabouts into a personal database could be setting people up for potential failure because of poor paperwork. The problem might be solved in so many other ways — like allowing for phone tracking, or by having an official look at a tournament schedule to figure out when a player would be available. The ITIA ran a trial that had a 90 percent success rate for finding and testing players without the specific hour of availability, but with the basic information about accommodations and schedules. That's part of why WADA approved it. Still, a two-tiered pool could seem off for tennis, which already brings plenty of tension between top players and everyone else.