Australia appear to have the most uncertainties. They were beaten 3-0 at home by India in their most recent T20 series and the selectors made several significant changes in picking a squad for South Africa and the global event.
Steve Smith was handed the captaincy, making him the leader in all three formats, while the squad includes three players who have yet to play in a T20 international - wicketkeeper Peter Nevill, left-arm spinner Ashton Agar and leg-spinner Adam Zampa.
Agar has played in two Tests and two one-day internationals, famously hitting 98 at number 11 on Test debut in the 2013 Ashes.
Zampa made his debut and played in two one-day internationals in New Zealand last month. Tye played in only two T20 internationals against India.
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Australia have a strong batting line-up, however, although this too could be problematical in terms of deciding on the best combination.
South Africa won two T20 internationals against England last month and will be strengthened by the returns of fast bowler Dale Steyn and wicketkeeper-batsman Quinton de Kock.
Steyn, 32, has missed most of the international season because of a groin injury suffered in the first Test against India in November and a shoulder injury in the first Test against England in December.
He said after his club outing that he had been ready to play for the past three weeks and was eager to get into action against the Australians.
De Kock was rested from the T20 series against England because of what was described as a minor knee injury. The selectors will have to decide which two out of De Kock, AB de Villiers and Hashim Amla will open the batting. The latter pair effectively won the second match against England with a century partnership.
But form in the warm-up series proved illusory. Australia won only one out of three matches in Bangladesh and failed to reach the knock-out stage, while South Africa reached the semi-finals.
Squads:
South Africa: Faf du Plessis (captain), Kyle Abbott, Hashim Amla, Farhaan Behardien, Quinton de Kock (wkt), AB de Villiers (wkt), JP Duminy, Imran Tahir, David Miller, Chris Morris, Aaron Phangiso, Kagiso Rabada, Rilee Rossouw, Dale Steyn, David Wiese.
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With seam bowler Nuwan Pradeep struggling to shake off a hamstring strain, Mathews said the uncapped Vishwa Fernando could make his debut.
Australia will definitely have to change their starting XI after Steve O'Keefe flew home with a pulled hamstring, with Jon Holland set to make his debut as a replacement.
Smith said Australia were determined to bounce back but admitted his team would "have to play a bit better than we did" in Pallekele.
Smith said Australia's batsmen would not only have to adapt to a dry track but also factor in the breeze from the nearby Indian Ocean.
Australia's last outing to the sub-continent saw them lose all four Tests against India in 2013 and they also lost both matches when Pakistan hosted them for a two-Test series in 2014 in the Gulf.
In a bid to beat Sri Lanka at their own game, Australia have hired the island's most famous spin bowler, Muttiah Muralitharan, as a consultant.
"The guys have been working very hard to try and get used to these conditions as much as possible," said Smith.