With the two-Test series due to start on April 28, the Pakistan Cricket board said Rahat had yet not recovered from a hamstring injury that he picked up during the first one-day international against Bangladesh earlier this month.
The PCB said the national selectors would decide on a replacement soon if required.
The Pakistan team has been hit by a spate of injuries to its key players since before the World Cup with the long list featuring Muhammad Hafeez, Sohail Khan, Junaid Khan, Bilawal Bhatti, Sohaib Maqsood, Rahat Ali, Yasir Shah.