Firdose Moonda South Africa correspondent, ESPNcricinfo 4 Minute Read

Chris Morris and Imran Tahir celebrate the run out of Suranga Lakmal Getty Images

And so it begins. South Africa's quest to claim the 2019 World Cup starts on Sunday, with the first of 21 ODIs before the tournament. The last time the team played in an ODI series, they lost 1-5 to a rampant Indian side whose wristspinners asked questions South Africa's batsmen didn't even understand, let alone answer.

Since then, the set-up has been rocked by two big retirements, Morne Morkel and AB de Villiers, and rebuilding is first on the agenda. Coach Ottis Gibson has identified separate phases of preparation and thinks it won't be until the last 10 matches, against Pakistan and Sri Lanka at home, that we can expect South Africa to field a XI that will closely resemble their World Cup team.

Before that, it's largely experimentation as South Africa try to find a winning combination. Here are the five questions they will want to answer over the course of the series:

Is a series in Sri Lanka a good starting point for World Cup preparation?

Instinct would say no, but the answer is yes. The expectation of flat pitches with plenty of runs everywhere in the world for ODIs would say it's as good as anywhere and batting coach Dale Benkenstein has come up with a reason. Given South Africa's problems against wristspin and Sri Lanka's team selection, Benkenstein sees the series as an opportunity for education. He hopes the batsmen will gain experience in picking the turn, something that they struggled with en masse against India earlier in the year and during the Tests. The results might not be pretty but it's something South Africa have to go through if they are to improve.

How much will South Africa miss AB de Villiers?

South Africa's performance in the Test series suggests that de Villiers' absence is already glaring. However, they've been used to his absence for long periods anyway. De Villiers had never taken a similar sabbatical in the shorter formats, even after stepping down as ODI captain following the 2017 Champions Trophy. He was always identified as their talisman and their mascot; the man who wanted to win a World Cup more than anyone else.

Now, South Africa have to go into the tournament without de Villiers, who decided to define his career on other things. South Africa may miss his reputation but a brief glance at his recent numbers suggest they aren't missing much, runs wise. De Villiers scored only 20 runs in three Champions Trophy matches, then returned from injury to blast 176 against Bangladesh but had a quiet series against India, scoring 56 runs in three innings.

JP Duminy gets down for a sweep AFP

Is JP Duminy really going to the World Cup?

Since his Test retirement before the start of last summer, Duminy has faded from the selection debate, but is likely to come back as the World Cup approaches. We may not even want to talk about when Duminy last scored a hundred because he only has four to his name (answer: the 2015 World Cup against Zimbabwe), but it's worth noting that he only has one half-century from his last 20 ODI innings. Duminy may get more opportunity to score bigger if he is promoted to de Villiers' No.4 spot, but he will need to start showing he can put in telling performances under pressure if he wants South Africa to rely on him at the World Cup.

Who after (or instead of) Imran Tahir?

Officially, Tahir has been rested from the ODI series because South Africa know what he can offer. Unofficially, the selectors may be thinking ahead in case they need someone else Tahir's form has dipped sharply in the 2017-18 summer, where he took seven wickets in seven matches at 42.50, including going wicket-less in three of the four matches against India. Tahir is finding form at Durham but the door is open for one of Keshav Maharaj or Tabraiz Shamsi to make a strong case to leapfrog Tahir in the World Cup squad.

Shamsi has slightly more ODI experience - seven caps to Maharaj's two - and was also named the domestic one-day cricketer of the year at the CSA annual awards but Maharaj's excellent showing in the second Test suggests the pair could be set for a showdown over the course of the series.

Is a Steyn-less attack enough?

South Africa have travelled with an inexperienced pace attack to Sri Lanka, made even more green by the absence of Morkel and Dale Steyn. Between them, Kagiso Rabada, Andile Phehlukwayo, Lungi Ngidi and Wiaan Mulder have 78 ODI caps, and 48 of those belong to Rabada. Steyn and Morkel have almost three times that number, 233, but the early indications are that neither will be at the World Cup.

Morkel has retired and Steyn has not played an ODI since October 2016 and during the course of his recovery from a recent heel injury, Gibson indicated Steyn should focus on red-ball cricket. However, in a recent interview, Steyn has suggested he wants to be in contention for the World Cup squad, and if selected will use the tournament as a white-ball swansong.

His offer is tempting for two reasons: South Africa could use his experience and they could also use the motivation of a marquee player to send off at the tournament. Though Faf du Plessis hinted the World Cup could mark the end for several seniors (Hashim Amla, for example), having Steyn - the bowler who sent down the ball the 2015 semi-final was last off - in the squad may serve as fuel to the Protea fire.