World 100m champion Torri Edwards' Olympic fate will be decided on Tuesday, the Court of Arbitration for Sport (CAS) announced in a statement.
Edwards has blamed a glucose tablet for the positive test
US sprinter Edwards tested positive for nikethamide at an athletics meeting in Martinique on 24 April but said she had taken the substance accidentally.
Edwards appeared before CAS on Monday to appeal against a two-year ban.
The CAS verdict is final and binding and Edwards will have no further avenue of appeal against the decision.
If Edwards' appeal is unsuccessful her place on the 100m team will go to 37-year-old two-time Olympic 100m champion Gail Devers.
And her berth in the 200m will be filled by Lashaunte'a Moore.
Edwards' defence rests on a product she took - coramine glucose that a physical therapist bought her which did not list nikethamide as an ingredient.
She was crowned world champion when compatriot Kelli White was banned after admitting taking drugs.
Edwards had qualified to compete in both sprint events in Athens after finishing second in the 100m and third in the 200m at the US trials.