Gill, who captains India in tests and one-day internationals, suffered a neck injury last month during India's first test against South Africa. He missed the rest of the two-test series and the subsequent ODI series.
The 26-year-old, who has played 33 T20 matches for India, will need a fitness clearance from the BCCI's Centre of Excellence in Bengaluru, where he is undergoing recovery.
Pandya demonstrated his fitness when he returned to domestic cricket on Tuesday, scoring 77 runs from 42 balls as he guided Baroda to a seven-wicket win over Punjab in the Syed Mushtaq Ali Trophy.
Rinku Singh and Nitish Kumar, who were part of India's T20 squad during the tour of Australia in October-November, have been left out of the 15-man squad.
The five-match T20 series will begin on December 9 in Cuttack and conclude in Ahmedabad 10 days later.
India squad
Suryakumar Yadav (Captain), Shubman Gill, Abhishek Sharma, Tilak Varma, Hardik Pandya, Shivam Dube, Axar Patel, Jitesh Sharma, Sanju Samson, Jasprit Bumrah, Varun Chakaravarthy, Arshdeep Singh, Kuldeep Yadav, Harshit Rana, Washington Sundar.