Returning De Villiers and in-form Ngidi in South Africa's ODI squad
AB de Villiers has been named in South Africa's one-day international squad for the first three matches of the series with Sri Lanka, while Lungi Ngidi is poised to win his first 50-over cap.
The former Proteas captain has not played for his country since last June after undergoing elbow surgery, but scored an unbeaten 134 from only 103 balls on his comeback for Northerns against Easterns in the CSA Provincial One-Day Challenge on Sunday.
Doubts have been raised over De Villiers' Test future after the 32-year-old revealed he will not face New Zealand, England or Bangladesh in the long form of the game this year but he was selected for Wednesday's Twenty20 international with Sri Lanka and is set to feature in at least some of the ODI series.
Fast bowler Ngidi has enjoyed a dream start to his international career, the 20-year-old taking six wickets in as many overs in his two T20I appearances against Sri Lanka.
And he has been rewarded with a further opportunity to impress, while all-rounder Chris Morris in line to win his first cap since last June.
Seamers Dale Steyn and Morne Morkel have not been considered for selection because of injury. Steyn is recovering from shoulder surgery and Morkel has a back problem.
Cricket South Africa selection convener Linda Zondi said: "It is wonderful to have AB back available both as player and leader. We are entering a very important phase of our preparation for the Champions Trophy Tournament in England as we only have 10 games left - the five here against Sri Lanka and another five in New Zealand - before we head for another major ICC event.
"The ODI squad is in [a] very good space at the moment after the clean sweep over Australia, but Sri Lanka will pose another stiff challenge.
"Ngidi has been rewarded for his excellent form in the current KFC T20 International Series and we are keen to see how he goes in the 50-overs format.
"He has not only impressed with the wickets he has taken and the skills he has displayed but with the energy and intensity he has brought to his game as well."
South Africa squad: Hashim Amla, Farhaan Behardien, Quinton de Kock, AB de Villiers (captain), JP Duminy, Faf du Plessis, Imran Tahir, David Miller, Chris Morris, Wayne Parnell, Lungi Ngidi, Andile Phehlukwayo, Dwaine Pretorius, Kagiso Rabada, Tabraiz Shamsi.