Siriwardana and Vandersay last played one-day internationals in October 2017, while Jeevan Mendis' previous appearance in the format came in the 2015 World Cup match against Afghanistan.
However, many of the regulars, including Niroshan Dickwella, Danushka Gunathilaka, Dinesh Chandimal, Upul Tharanga and Akila Dananjaya, were excluded from the squad altogether, with Oshada Fernando, Angelo Perera, Kasun Rajitha, and Wanindu Hasaranga placed on standby.
The axe from the selectors came after Sri Lanka's recent tour to South Africa, where they succumbed to a 5-0 defeat in the ODI series. Kusal Mendis and Oshada Fernando, Sri Lanka's highest run-scorers in that series, have retained their place in the squad.
Angelo Matthews, one of the most experienced members with 218 ODI appearances to his name, made a comeback to the squad after being dropped from the ODI set-up last year over fitness concerns. Thisara Perera, Isuru Udana, Dhananjaya de Silva, Jeewan Mendis and Siriwardana complete the all-rounder contingent alongside Matthews.
Malinga, who was named skipper for the South Africa tour, will spearhead their bowling attack in the tournament, with Dimuth Karunaratne replacing him at the helm. Nuwan Pradeep and Suranga Lakmal slot into the seam department, while Vandersay comes in as the only specialist spin-bowler.
Squad: Dimuth Karunaratne (c), Avishka Fernando, Lahiru Thirimanne, Kusal Perera, Kusal Mendis, Angelo Mathews, Dhananjaya de Silva, Jeffery Vandersay, Thisara Perera, Isuru Udana, Lasith Malinga, Suranga Lakmal, Nuwan Pradeep, Jeevan Mendis, Milinda Siriwardana