Cape Town - Springbok coach Rassie Erasmus has explained his decision to go into Friday's crunch Rugby World Cup clash against Italy with a 6-2 split on the bench. 

When he named his side for the clash in Shizuoka on Tueday, Erasmus sprung a surprise by including six forwards and just two backline players - Herschel Jantjies and Frans Steyn - among his substitutes. 

The international norm is to include five forwards and three backline players.

The Boks will start the contest as overwhelming favourites, but they know that a shock loss to the Italians would almost certainly spell the end of their World Cup charge without getting out of the group stages. 

The decision to go forward-heavy on the bench, Erasmus says, was down to the fact the Springboks have a six-day turnaround between their matches against Namibia and Italy and then just four days between Italy and their final pool match against Canada on October 8. 

"It's been taxing on the forwards so we think that by selecting almost two full packs it will spread the load more and that will help us," Erasmus said.

"It might look like we're overloading, but by doing it this way we're actually helping them spread the load a little bit better."

The versatility of a player like Steyn, Erasmus added, helped make such a decision possible. 

"If we do get two injuries in the backline and then a third, then we'll have to get very creative in how we're going to cover that, but we've got some plans there," the coach said.

"I think where we're really fortunate is that a guy like Frans can cover No 10, 12 and 15 which is a luxury.

"Damian (De Allende) has played 13 for us a lot, Cheslin (Kolbe) can cover 15 before, Willie (Le Roux) has played wing before, Faf (De Klerk) has played a high level of flyhalf ... I think in extreme circumstances of bad luck with injuries, we are versatile enough with our backline combinations to cover that."

The Springboks also confirmed on Tuesday that Jesse Kriel had been replaced in the squad by Damian Willemse, who is another player with the ability to cover numerous positions in the backline. 

Kick-off on Friday is at 11:45 (SA time). 

Teams:

South Africa

15 Willie le Roux, 14 Cheslin Kolbe, 13 Lukhanyo Am, 12 Damian de Allende, 11 Makazole Mapimpi, 10 Handre Pollard, 9 Faf de Klerk, 8 Duane Vermeulen, 7 Pieter-Steph du Toit, 6 Siya Kolisi (captain), 5 Lood de Jager, 4 Eben Etzebeth, 3 Frans Malherbe, 2 Bongi Mbonambi, 1 Tendai Mtawarira

Substitutes: 16 Malcolm Marx, 17 Steven Kitshoff, 18 Vincent Koch, 19 RG Snyman, 20 Franco Mostert, 21 Francois Louw, 22 Herschel Jantjies, 23 Frans Steyn

Italy

TBA