LAUSANNE, Switzerland - A ruling on Maria Sharapova's appeal of her two-year doping ban has been postponed until September, ruling her definitively out of the Olympics in Rio de Janeiro.

The Court of Arbitration for Sport said on Monday that Sharapova and the International Tennis Federation agreed to defer the decision, which had been due to be issued by next Monday.

CAS, the highest court in sports, said both parties wanted more time to prepare their case and also cited "scheduling conflicts."

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A verdict is expected by Sept. 19, the court said.

Sharapova, a five-time Grand Slam champion and former No. 1-ranked player, tested positive for meldonium at the Australian Open in January and received a two-year ban from the ITF. Sharapova, who faced up to a four-year suspension, lost all ranking points and prize money she earned in Melbourne. She filed an appeal last month, seeking to overturn or reduce the sanction.

She has called the decision to ban her for two years "an unfairly harsh" punishment to the Court of Arbitration for Sport.

The parties agreed then to an "expedited procedure" that would allow CAS to issue its ruling this month. Had the suspension been annulled, that would have made Sharapova eligible for the Olympics in August.

The decision to push back the ruling to September also rules out any possibility of Sharapova being cleared to play in the U.S. Open, which runs from Aug. 29-Sept. 11.

"Due to the parties requiring additional time to complete and respond to their respective evidentiary submissions, and several scheduling conflicts, the parties have agreed not to expedite the appeal," CAS said in the statement.

Sharapova's lawyer, John Haggerty, said the decision was by mutual agreement and will give her team additional time to prepare its case.

"CAS is the court of final appeal and this extension will be helpful." Haggerty said in a statement. "We are hopeful Maria's suspension will be reduced, but in all cases, these additional two months will not impact our expectations of what can be achieved."

Sharapova acknowledged taking meldonium before each match at the Australian Open. She said she had not been aware that meldonium, also known as mildronate, had been banned by World Anti-Doping Agency as of Jan. 1.

An independent three-person panel appointed by the ITF ruled that Sharapova did not intend to cheat because she didn't know meldonium was banned, but that she bore "sole responsibility" and "very significant fault" for the positive test.

Sharapova said she first was prescribed the Latvian-made drug, typically used for heart conditions, for medical reasons in 2006.

Her ban is due to end on Jan. 25, 2018, which would keep her out of eight Grand Slam tournaments, along with the Olympics.

The future of the former No. 1-ranked player is in doubt. She is the owner of five Grand Slam titles who is one of the sports most well-known stars and - thanks to a wide array of endorsements - highest-earning athletes in the world.

She is one of 10 women in tennis history with a career Grand Slam - at least one title from each of the sport's four most important tournaments. Sharapova was the 2004 Wimbledon champion at age 17; No. 1 in the rankings at 18; U.S. Open champion at 19; Australian Open champion at 20. An operation to her right shoulder in 2008 took her off the tour for months, and her ranking dropped outside the top 100. But she worked her way back, and in 2012, won the French Open, then added a second title in Paris two years later.

Now comes a dark chapter to the story of someone who was 9 years old when her father moved her from Russia to Florida to pursue a tennis career.