Nick Kyrgios Photo: PHOTOSPORT
Sinner failed two drug tests in March but has been cleared of wrongdoing by an independent tribunal.
The decision comes just days before the Italian is set to play at the fourth and final major of the year the US Open, in New York.
The tribunal accepted the Australian Open champion's explanation that the anabolic agent clostebol entered his system from a member of his support team through massages and sports therapy.
Sinner said his physio, Giacomo Naldi, applied an over-the-counter spray containing clostebol to his own skin to treat a small finger wound and then administered massages between 5 to 13 March without using gloves, according to the International Tennis Integrity Agency.
Jannik Sinner. Photo: PHOTOSPORT
Naldi was unaware that the product he had used on his cut contained clostebol, Sinner said.
Clostebol is a steroid that can be used to build muscle mass.
But the saga has invited an added layer of attention a day after he won a key US Open tune-up event in Cincinnati.
Australian player Nick Kyrgios lambasted the Sinner ruling.
"Ridiculous - whether it was accidental or planned. You get tested twice with a banned substance ... you should be gone for 2 years. Your performance was enhanced," Kyrgios said on X.
Seven time major winner and ESPN analyst John McEnroe also expressed concern.
"It's certainly surprising and shocking, at this moment, especially to me when it happened apparently in March," said McEnroe.
"I don't know how they differentiate between one person, you know, sort of saying he was unaware of it and the reasons behind it and then someone else who says the same thing, you know, gets suspended."
Sinner's first positive sample was taken on 10 March with a second eight days later. A provisional suspension was applied with each positive test but he was allowed to keep playing after his team filed urgent appeals.
"Sinner's results, prize money and ranking points from the ATP Masters 1000 event at Indian Wells, where the player tested positive in competition for clostebol, are disqualified," the International Tennis Integrity Agency said in a citing World Anti-Doping Code and Tennis Anti-Doping Programme regulations.
WADA said it would review the decision and reserved the right to appeal. Sinner, who has always maintained his innocence, said the amount of clostebol found in his system was less than a billionth of a gram.
"I will now put this challenging and deeply unfortunate period behind me," the 23-year-old said in a statement posted to social media.
The men's ATP Tour said the saga "underscores the need for players and their entourages to take utmost care in the use of products or treatments."
Sinner is the latest tennis player to become embroiled in a doping case, after twice major winner Simona Halep had her four-year doping ban cut to nine months this year after testing positive for a prohibited substance at the 2022 US Open.
Halep argued she had unwittingly ingested the blood-booster roxadustat through contaminated nutritional supplements.
-Reuters