Also back in the squad are openers Fakhar Zaman, who missed the Test series against New Zealand with a knee injury, and Shan Masood, who comes in following the Test retirement of Mohammad Hafeez. Mohammad Rizwan, who has previously played one Test in Hamilton in November 2016, has also been included as the second wicketkeeping option behind captain Sarfraz Ahmed.
A poor run of limited-overs form had led to Amir being dropped from Pakistan's squad in all three formats during their ongoing home season in the UAE. He missed the Test series against Australia and New Zealand, but he has shown excellent form in first-class cricket, picking up 23 wickets in his last four Quaid-e-Azam Trophy matches at an average of 13.61.
Inzamam-ul-Haq, Pakistan's chief selector, said Amir's drop in form had come about as a result of his heavy workload since returning from a five-year spot-fixing ban in January 2016.
"Amir is a wonderful bowler and we all know how skillful he is," Inzamam said. "But since his return he went through a lot of workload and didn't get enough time to rest. He was always in our plans. He was dropped for his good, to allow him to go back and not only rest but also work on his deficiencies."
Shadab, meanwhile, didn't play any of the Tests against Australia and New Zealand, nursing a long-term groin injury - although he did play the limited-overs matches against New Zealand. His return has led to the exclusion of Bilal, who made his Test debut during the home season and picked up 16 wickets in five Tests - including two five-wicket hauls - at an average of 26.50.
Fakhar has been undergoing rehabilitation at the National Cricket Academy (NCA) in Lahore since sustaining his knee injury in October. Initial media reports suggested he would be out for three to five weeks, but his recovery has gone quicker than expected and he has already returned to batting practice, facing more than 100 balls at the NCA nets on Thursday.
Fast bowler Mohammad Abbas was another player under a fitness cloud, having missed the final Test against New Zealand this week with a shoulder injury, but he is expected to be fit in time for the Boxing Day Test.
Amir and Abbas are joined by Hasan Ali, Shaheen Afridi and the allrounder Faheem Ashraf in a five-member pace contingent. The batting ability of Faheem and Shadab will give Pakistan a certain degree of flexibility in terms of the composition of their bowling attack, leading to the possibility of their fielding twin legspinners in Shadab and Yasir Khan.
Squad Imam-ul-Haq, Fakhar Zaman, Shan Masood, Azhar Ali, Haris Sohail, Asad Shafiq, Babar Azam, Sarfraz Ahmed (capt & wk), Mohammad Rizwan (wk), Yasir Shah, Shadab Khan, Mohammad Abbas, Hasan Ali, Mohammad Amir, Faheem Ashraf, Shaheen Afridi