Cape Town - Proteas captain Faf du Plessis, addressing Johannesburg media on Tuesday ahead of three ODIs and one T20I in Australia, provided some valuable insight into the preparations for next year's World Cup and what the side for that tournament might look like.  

Du Plessis, thanks to a couple of niggling injuries, has had his participation in Proteas colours disrupted so far in 2018. 

Those worries are a thing of the past now, and moving forward he will be central to everything the Proteas do between now and May next year when their quest to win a first World Cup gets underway. 

With 13 ODIs left between now and then, time is running out. 

Almost everything that the Proteas do these days is with the World Cup in mind, so it was no surprise that the tournament was a central theme of Du Plessis' press conference. 

The skipper believes that he and coach Ottis Gibson have settled on about 85% of the World Cup squad, while the three ODIs in Australia will provide some players with a final opportunity. 

The side is taking serious shape. 

While he is currently missing with a finger injury, Hashim Amla will open the batting with Quinton de Kock. 

Du Plessis added that the No 3 slot in the World Cup line-up was likely to be a "straight shootout" between Aiden Markram and Reeza Hendricks who the skipper said were "both very good players". 

Du Plessis himself, on the request of coach Ottis Gibson, looks the likeliest option at No 4. 

"I understand where the coach is coming from," Du Plessis explained when discussing his batting position. 

"No 4 is a position where you need to be versatile and play different situations and we also need that experience in the middle order."

JP Duminy is also currently out injured but will be fit for the Sri Lanka series in February, and he is expected to bat at No 5. 

While Du Plessis did not discuss the No 6 slot, David Miller is surely still the favourite to bat there. 

Perhaps the most interesting revelation, though, is that the Proteas are leaning towards fielding four specialist bowlers in Dale Steyn, Kagiso Rabada, Lungi Ngidi and Imran Tahir. 

That would leave room for one all-rounder at No 7. 

"We've spoken a lot about the No 7 role that we would like to experiment in (in Australia)," Du Plessis said.

"Do you go for an out-and-out batter and play four bowlers, or do you go with two allrounders?

"Our school of thought at the moment is that we've got four very good wicket takers, and we want to see how we can have all of them playing at all times and then find out who our best No 7 is.

"In that, you need someone who can bowl as a fifth bowler as well and that's where the tricky part comes in."

The allrounder options in Australia come in the form of the returning Chris Morris and Dwaine Pretorius. 

Farhaan Behardien is also with the squad, though it is hard to see him bowling as many overs as Morris and Pretorius. 

For some of those players, this is last chance saloon. 

"Australia will probably be the last time that we would look to experiment a bit more," said Du Plessis.

"When you get closer to the World Cup you would like the guys to play as much in their roles that we think will suit them best.

"For some, this is an opportunity to put their pegs in the ground and make a play to be a part of that World Cup 15."

The first ODI takes place on November 4.