The 23-year-old finger spinner, who has a variety of deliveries in his armoury, is expected to make his Test debut and will partner Muttiah Muralitharan, the most successful bowler in Tests.
Earlier this month, Mendis, who bowls a mixture of off-breaks, leg-breaks, googlies and top-spinners, claimed six for 13 against India to help his team win the Asia Cup.
Mendis, born in Moratuwa, a city on the southwestern coast of the Emerald Island, was reportedly fast-tracked after his unconventional skills were noticed last year by coaches of the national cricket academy when he was playing in the B division league.
"From the day we spotted him, he had all the variations. Not only was he gifted, he was also very calm and always ready to listen," Anusha Samaranayake, pace-bowling coach at the academy, told the Indian Express newspaper.
Mendis announced his arrival on the international stage with three for 39 off 10 overs against the West Indies in a one-day series in the Caribbean in April.
Meanwhile, tearaway fast bowler Lasith Malinga and all-rounder Ferveez Maharoof have been ruled out of the first Test after the selectors decided to allow them more time to recover from their injuries.
The selectors decided to allow Malinga and Maharoof more time to recover from their injuries and waited till the three-day warm up game at NCC finished to name the final 15 as some of the players were given opportunity to prove their fitness and form in that game.
In the opening Test, starting here on Wednesday, Sri Lanka should take the field with just two fast bowlers. In that case either left-armer Thilan Thushara or right-arm seamer Nuwan Kulasekera will share the new ball with Chaminda Vaas.
Fast bowler Dilhara Fernando was also ruled out after suffering a knee pain during a three-day practice game against India over the weekend.
Sri Lanka Squad: Mahela Jayawardene (capt), Kumara Sangakkara (wk), Malinda Warnapura, Thilan Samaweera, Michael Vandort, Tillakaratne Dilshan, Chamara Silva, Chamara Kapugedera, Thilan Thushara, Chaminda Vaas, Prasanna Jayawardene (wk), Muttiah Muralitharan, Ajantha Mendis and Nuwan Kulasekera.