With the addition of these two players now, the Sri Lankan team has affected five changes to its original World Cup squad.
Earlier, opening batsman Upul Tharanga replaced fellow left handed opener Dimuth Karunaratne, while another opening batsman Kusal Janith Perera was sent as cover for injured Rangana Herath.
Sri Lankan selectors said that Janith Perera would now take the place of the injured middle order batsman Dinesh Chandimal.
The 24-year-old left hander Vithanage has played six ODIs, while the 22-year-old right arm off spinner Kaushal is yet to make an ODI appearance. He made his debut in the longest version of the game in the recent Test series against New Zealand in January.
