T20 captain Shahid Afridi was also included among the 26 players for the camp, reports dawn.com.pk.
Amir was was suspended for five-years after he was found guilty of spot-fixing in 2011 that curtailed his promising career. He was allowed to return to competitive cricket earlier in the year.
The 26 players, picked by the selection committee, are likely to form the core of Pakistan's squad for next year's World Twenty20 in India.
"The main objective of the camp is to improve the overall physical fitness of all players and to enhance the technical aspect of each player’s game and to prepare them for the upcoming international events," the PCB said in a statement.
"Shaharyar Khan, Chairman PCB has approved the names of 26 players picked up by the PCB National Selection Committee for the fitness camp."
"Will try my best to give 100% to my country," Amir tweeted on Friday.
Will try my best to give 100% to my country..
— Mohammad Amir (@iamamirofficial) December 18, 2015
Amir recently played for team Chittagong Vikings in the Bangladesh Premier League T20 tournament.
Players selected for the training camp: Ahmed Shehzad, Mohammad Hafeez, Sharjeel Khan, Azhar Ali, Shoaib Malik, Babar Azam, Iftikhar Ahmed, Umar Akmal, Asad Shafiq, Shahid Afridi, Sarfraz Ahmed, Mohammad Rizwan, Bilal Asif, Sohaib Maqsood, Amir Yamin, Wahab Riaz, Anwar Ali, Mohammad Irfan, Umar Gul, Rahat Ali, Junaid Khan, Ruman Raees, Imad Wasim, Yasir Shah, Saad Nasim, Mohammad Amir.