Rassie Erasmus and Mario Ledesma will take their first steps in the Rugby Championship as head coaches on Saturday when South Africa and Argentina meet in the opening round of another tournament expected to be dominated by New Zealand.

Erasmus and Ledesma both took over faltering teams and must rebuild with just over a year to go until the Rugby World Cup in Japan.

South Africa and Argentina were World Cup semifinalists in 2015 but have fallen far off the pace set by world champion New Zealand, which has won five of the last six Rugby Championships.

Erasmus has had more time to settle in.

Rassie Erasmus. (AP Photo/Themba Hadebe, File)

He led South Africa to a 2-1 series win over England in June that sparked talk of a Springboks revival even though the Boks have only won two out of four tests in Erasmus' young reign.

Still, it's far more positive than the dire two years South Africa had under predecessor Allister Coetzee.

To start the Rugby Championship, Erasmus was able to bolster his pack with four key forwards who missed the England series.

Hooker Malcolm Marx, lock Eben Etzebeth and No. 8 Warren Whiteley all returned from injury to take their places in Saturday's starting lineup against the Pumas in Durban. Experienced flanker Francois Louw also returns to give the Boks a specialist openside after captain Siya Kolisi filled in there in the England series.

Kolisi shifts back to blindside flanker and retains the captaincy despite the return of Whiteley, who captained under Coetzee but is available for the first time to Erasmus.

Fit-again Springboks lock Eben Etzebeth. (AP Photo/Francois Mori)

Marx and Etzebeth, especially, will give the Springboks extra forward power against the physical Argentina scrum, although No. 8 Duane Vermeulen is a glaring absence after he was South Africa's best player against England. Vermeulen is not in the squad for the Rugby Championship as he finalizes a move back to South African rugby from French club Toulon.

Erasmus' latest move to increase South Africa's depth is to give uncapped 20-year-old utility back Damian Willemse a place on the bench.

"The challenge will be pressure and expectation," Erasmus said, "but if he gets through that he is a talent and maybe he can do it for us at the World Cup as a utility player. I can understand why the hype is there."

Argentina captain Agustin Creevy, left, and South Africa's Steven Kitshoff. (AP Photo/Natacha Pisarenko)

Ledesma, like Erasmus a former international player, has been Argentina coach for just over two weeks.

Daniel Hourcade resigned in June after three straight home losses to Wales and Scotland. Argentina failed to win a game in the Rugby Championship last year for the first time since 2013.

But although new to the Pumas, Ledesma is working in familiar terrain because of his parallel role as coach of the Jaguares Super Rugby team. All but one of the Argentina squad for the Rugby Championship play for the Jaguares. He was also Australia's forwards coach in the Rugby Championship from 2015 to the end of last season.

One of Ledesma's first selection decisions for Argentina was to bring that one non-Jaguares player into the fold, with Saracens prop Juan Figallo set to start in Durban in his first test since the 2015 World Cup.

New Argentina coach Mario Ledesma. (AP Photo/Natacha Pisarenko)

Ledesma adds an air of confidence after leading the Jaguares to the Super Rugby playoffs this season for the first time. The 45-year-old Ledesma has worked as an assistant coach in France as well as Australia and under current Wallabies coach Michael Cheika at three teams.

He'll get to test his development against Cheika later in the Rugby Championship after starting with back-to-back games against the Springboks.

"Their new coach comes with a lot of technical knowledge and experience from his previous coaching roles, which is sure to add more firepower to their traditional strengths," Erasmus said of Ledesma's possible effect on Argentina. "They will be very confident as a result of the Jaguares' great run."

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South Africa: Willie le Roux, Makazole Mapimpi, Lukhanyo Am, Andre Esterhuizen, Aphiwe Dyantyi, Handre Pollard, Faf de Klerk; Warren Whiteley, Siya Kolisi (captain), Francois Louw, Pieter-Steph du Toit, Eben Etzebeth, Frans Malherbe, Malcolm Marx, Tendai Mtawarira. Reserves: Bongi Mbonambi, Steven Kitshoff, Thomas du Toit, Marvin Orie, Marco van Staden, Embrose Papier, Lionel Mapoe, Damian Willemse.

Argentina: Emiliano Boffelli, Bautista Delguy, Matias Moroni, Bautista Ezcurra, Ramiro Moyano, Nicolas Sanchez, Gonzalo Bertranou; Javier Ortega Desio, Marcos Kremer, Pablo Matera, Matias Alemanno, Guido Petti, Juan Figallo, Agustin Creevy (captain), Nahuel Tetaz Chaparro. Reserves: Diego Fortuny, Santiago Garcia Botta, Santiago Medrano, Tomas Lavanini, Tomas Lezana, Martin Landajo, Santiago Gonzalez Iglesias, Juan Cruz Mallia.