Sri Lanka batsman Dimuth Karunaratne has been ruled out of the remainder of the World Cup after breaking a finger in practice.
Left-arm spinner Rangana Herath is also expected to miss Sunday's crucial game with Australia after injuring his hand in the nine-wicket victory over England.
The Lions have already lost all-rounder Jeevan Mendis and fast bowler Dhammika Prasad from their original squad for the tournament.
Karunaratne made scores of 14 and 23 in Sri Lanka's first two Pool A games, but was not required in the lower order in their last two wins.
Leg-spinning all-rounder Seekuge Prasanna comes into the squad as his replacement, while opening batsman Kusal Perera, who played throughout the winter series against England, has now been put on standby for Herath.
Sri Lanka are currently second in the Pool A table with six points from a possible eight.
