Published: 2017-04-15 20:33:59 BdST
The 29-year-old underwent an out-of-competition test in Dubai in January and the sample was tested at the World Anti-Doping Agency (WADA) accredited laboratory in Salt Lake City.
The 'A' sample tested positive for clenbuterol, a banned anabolic agent, the ICC said in a statement.
"In accordance with the ICC Anti-Doping Code ... Shahzad will be provisionally suspended, with such suspension coming into effect on 26 April 2017, unless he exercises his right to challenge the imposition of the provisional suspension before such date," the sport's governing body said.
Shahzad, who has played 58 one-day internationals for Afghanistan, has five days from the notice of the positive test to ask for his 'B' sample to be tested.
He has 12 days to determine whether he will challenge the provisional suspension. If he does elect to have a hearing then the ban will not be imposed until the outcome is known.
If he does not respond within 14 days, the ICC will have deemed him to have waived his entitlement to a hearing and admitted to having committed the anti-doping rule violation.