Top-ranked tennis player Jannik Sinner tested positive twice for an anabolic steroid in March, but he will not be suspended after the International Tennis Integrity Agency on Tuesday determined that the banned substance entered his system unintentionally through a massage from his physiotherapist.

"I will now put this challenging and deeply unfortunate period behind me," Sinner posted to Instagram on Tuesday. "I will continue to do everything I can to ensure I continue to comply with the ITIA's anti-doping programme and I have a team around me that are meticulous in their own compliance."

Sinner won the Cincinnati Open on Monday and will be among the favorites at the US Open, which starts in New York next week.

During the Indian Wells hard-court event in March, Sinner tested positive for low levels of a metabolite of clostebol, a banned anabolic steroid that can be used for ophthalmological and dermatological use. It's the same drug for which San Diego Padres star Fernando Tatis Jr. was suspended by MLB.

Sinner tested positive again eight days later in an out-of-competition sample.

He was provisionally suspended because of those test results, but he successfully appealed and was allowed to keep competing on tour. He will, however, lose the $325,000 and 400 points that he had earned at the tournament in Indian Wells.

In its ruling, the ITIA said the low levels of clostebol from the tests on March 10 and March 18 were "a result of contamination from a support team member, who had been applying an over-the-counter spray containing clostebol to their own skin to treat a small wound."

The support team member then passed along the anabolic agent transdermally via "daily massages and sports therapy" to Sinner.

In its statement, the ITIA it "did not oppose the player's appeals to lift the provisional suspension" and that "the violation was not intentional."

An independent panel held a hearing on Aug. 15 and "determined a finding of No Fault or Negligence applied in the case, resulting in no period of ineligibility," according to the ITIA.

ITIA CEO Karen Moorhouse said "Sinner and his representatives fully cooperated" with her group's "thorough investigation."

The World Anti-Doping Agency and Italy's anti-doping body are both allowed to appeal the decision.

"We are encouraged that no fault or negligence has been found on Jannik Sinner's part," the ATP Tour said in a statement. "We would also like to acknowledge the robustness of the investigation process and independent evaluation of the facts under the Tennis Anti-Doping Program (TADP), which has allowed him to continue competing.

"This has been a challenging matter for Jannik and his team, and underscores the need for players and their entourages to take utmost care in the use of products or treatments. Integrity is paramount in our sport."

Sinner made his debut at No. 1 in the ATP rankings in June and is considered among the top stars of the new generation in men's tennis, along with Carlos Alcaraz.

The Italian, who turned 23 on Friday, won the Australian Open in January for his first Grand Slam title. He reached the semifinals at the French Open in June and the quarterfinals at Wimbledon in July, before sitting out the Paris Olympics with tonsillitis.

The Associated Press contributed to this report.