Sharapova appealed to Cas but both the 29-year-old Russian and the International Tennis Federation need more time to prepare their cases.
The Rio Olympics start on 5 August.
"Maria Sharapova and the International Tennis Federation (ITF) have agreed to defer the Cas decision until September 2016," said a statement.
"A decision is expected to be issued by 19 September 2016."
Sharapova tested positive for meldonium at the Australian Open in January.
-What is meldonium?
Also known as mildronate, it became a banned substance on 1 January, but Sharapova claimed she had been using it since 2006 for health issues.
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