Fast bowlers Tanvir Ahmed and Rahat Ali have been added to the Pakistan squad ahead of the first Test against South Africa which starts in Johannesburg on Friday.
A PCB spokesman said the decision followed a request from the touring team's management.
"They have taken this decision after considering the conditions and duration of the tour in South Africa," the spokesman said. "Both players will arrive before the first Test."
The squad already includes pacemen Umar Gul, Junaid Khan, Mohammad Irfan and the uncapped Ehsan Adil.
Tanvir, 34, who has played four Tests, made his last appearance for Pakistan in a one-day match against Ireland last year.
Left-armer Rahat, 24, has played just one one-day international against Sri Lanka last June.
The first game of the three-match Test series takes place at the New Wanderers Stadium followed by games at Cape Town and Centurion.