South African cricketer Zubayr Hamza has agreed to a voluntary suspension after testing positive for a prohibited substance, Cricket South Africa announced on Wednesday. Hamza, 26, has played in six Test matches and one one-day international. According to a CSA statement, Hamza tested positive for the substance Furosemide following an International Cricket Council anti-doping test on January 17. Furosemide is a diuretic, prescribed to treat hypertension and reduce swelling caused by fluid build-up in the body. It is on the World Anti-Doping Agency's banned list because of concerns that it may mask other drugs.