Chandimal's appointment comes in the wake of Sri Lanka T20 captain Lasith Malinga failing a fitness test on his injured left knee which has ruled him out of the ongoing tour of New Zealand.
"Lasith countered pain on his left knee during the fitness test, and we have decided to keep him out of the New Zealand tour," said chief selector Kapila Wijegunawardene.
"The injury will take about two to three weeks for him to recover."
Fast bowler Suranga Lakmal who is already in New Zealand has been drafted into the Sri Lanka T20 side to replace Malinga.
Left-hand opening bat Danushka Gunathilaka has also been included in the T20 squad to replace Kusal Perera who is currently under suspension by the ICC. Sri Lanka plays New Zealand in two T20I at Maunganui and Auckland on January 7 and 10 respectively.
