Sri Lanka possible XI-
1. Upul Tharanga (Left-Hand Batsman)
2. Niroshan Dickwella (Wicket-Keeper)(Left-Hand Batsman)
3. Kusal Mendis (Vice-Captain)(Right-Hand Batsman)
4. Kusal Perera (Left-Hand Batsman)
5. Angelo Mathews (Captain)(Right-Hand Batsman)
6. Dasun Shanaka (Right-Hand Batsman)(Right-Arm Medium)
7. Dhananjaya De Silva (Right-Hand Batsman)(Right-Arm Off-Spin)
8. Thisara Perera (Left-Hand Batsman)(Right-Arm Medium)
9. Akila Dananjaya (Right-Arm Off/Leg-Spin)(Left-Hand Batsman)
10. Kasun Rajitha (Right-Arm Medium-Fast)
11. Lahiru Kumara (Right-Arm Fast)
12. Lakshan Sandakan (Left-Arm Chinaman)
13. Shehan Jayasuriya (Left-Hand Batsman)(Right-Arm Off-Spin)
14. Suranga Lakmal (Right-Arm Medium-Fast)
15. Prabath Jayasuriya (Left-Arm Orthodox)
If possible these players must be recalled to the squad for the last 3 ODIs as they have proven to be strike bowlers for Sri Lanka like what the South Africans have right now.
1. Lasith Malinga (Right-Arm Fast)(If Willing)
2. Dushmantha Chameera (Right-Arm Fast)(If Fit)
3. Shehan Madushanka (Right-Arm Fast)
Shehan Jayasuriya has proven he does the same thing as Prabath Jayasuriya like containing the batsman with the ball being economical. Therefore since Sri Lanka`s batting is looking really weak, they should keep Shehan in the XI since he was playing good in the 2nd ODI and was unlucky to get out.
I`ve always believed Dasun Shanaka is the next Angelo Mathew as he can absorb pressure. With Thisara Perea, Kusal Perea and Dasun Shanaka and even Angelo Mathews, since he gets back into form, can rebuild innings even if the top order fails. All four players are match winner they can absorb pressure and then put pressure on the opponent's bowlers.
Another possible change to consider is replacing Kusal Mendis with Dhananjaya De Silva since Kusal Mendis job is to rebuild the innings when the openers fail but Kusal Mendis has been in poor form this whole Tour at home.
Sri Lanka really needs to address their batting issue and a simple thing that could help is bowling first as if their bowlers can restrict South Africa to a decent total then Sri Lanka can bat accordingly to the run rate instead of having the pressure to set up a big total. Angelo captaincy has been poor in some areas like using Akila too early in the innings and using Thisara too late. In my opinion, Thisara should bowl first change after the first two main fast bowlers have bowled and then Akila should come in the middle overs and take crucial wickets and dry out the runs by having an economical rate of around 4.
Sri Lanka not using Dasun Shanaka in XI has suprised me as he is the X factor player in the Team. Dasun Shanaka has reputation a of hitting big sixes and fours proving the team with a quick fire 50 but also has shown he can hit a quick fire 100 as well. He has been a crucial pillar in the Sri Lanka A team where he has saved matches with both bat and ball in ALL FORMANTS like in Test , ODIs and especially in T20s. I believe Dasun Shanaka is the solution to Sri Lanka`s batting issue and he will be an important player in the World Cup 2019 in England with both Bat and Ball.