South Africa batsman Zubayr Hamza has tested positive for the banned diuretic Furosemide, the country's cricket federation said on Wednesday.
The 26-year-old Hamza is not disputing the positive test and has agreed to a "voluntary suspension" starting immediately while the case is investigated, Cricket South Africa said.
"Zubayr has been able to identify how the substance entered his system," CSA said in a statement.
"The process to follow will entail presenting evidence that there was no fault or negligence, or no significant fault or negligence on the part of Zubayr."
Furosemide is not a performance-enhancing drug but is banned because it can be used to mask other substances.
Hamza tested positive following a doping test on Jan. 17, CSA said. He went on to play for South Africa in the first test in New Zealand last month.
Hamza has played six tests for the Proteas but hadn't represented his country in the long format for two years before his appearance against New Zealand.
He withdrew from South Africa's ODI squad last week ahead of the home series against Bangladesh.