Australia and New Zealand may view it with a healthy dosage of scepticism, but the Springboks are literally falling like ten-pins.

Already 21 of South Africa's leading players have been ruled out of the away leg of the Tri-Nations, which caused such a big stir in Australasia, but Friday that number rose to 23 - with two other players suffering injuries, but remaining part of the tour squad.

So bad has it become that Bok coach Peter de Villiers, desperate to find some back-up for his fast-dwindling front row stocks, called up a player that has not had any game time since May and is officially still injured.

De Villiers confirmed of Friday that star No.8 Pierre Spies has joined the list of players formally ruled out of the Tri-Nations games against the Wallabies (in Sydney on July 23) and the All Blacks (in Wellington a week later).

Spies, who was on holiday till Thursday, was asked to report for a medical check-up in Cape Town.

"He has a groin injury," De Villiers said, adding that his squad of injured stay-at-home stars.

The 23rd player to be formally ruled out through injury is Bulls fullback Zane Kirchner, who has a shoulder injury.

"It is not that bad," DE Villiers said, adding: "If we were in trouble [with outside backs] we could have taken him along.

"However, we have to be sensible with all our players. We don't know what is going to happen down the line and we may need him in the weeks to come.

"We decided to send him back fort rehabilitation and hopefully he'll be available for the home games [of the Tri-Nations series in August]."

But that is not where it stops.

"It never rains, but pours," the Bok mentor said, confirming that two members of the squad suffered injuries at training this week.

"Coenie [Oosthuizen] injured his ankle yesterday [Thursday] and Johann Muller damaged his hamstring this [Friday] morning," De Villiers said, adding that they should be fine to play.

But the injury of Oosthuizen has created a problem in a squad that now has just two fit specialist props - Bulls Dean Greyling and Werner Kruger.

"On Monday we will bring in another injured player, CJ van der Linde, to be assessed," DE Villiers said of the Stormers prop that hasn't played since returning home from the Stormers' Australasian tour in May.

"At this stage it looks like he won't be fit to go to the World Cup, because of his [groin] injury, but we don't have any other option but to bring him back to asses him again.

"If there is a 10 percent that he can play, he will go on tour [to Australasia]."

De Villiers admitted that Bok captain John Smit, at a push, can help cover at prop.

However, he sees his captain as a hooker only.

"Yes, he can cover, but he is definitely [in the squad] as a hooker."

De Villiers also dismissed the notion of calling up Cheetahs tighthead prop WP Nel.

He felt the Cheetahs man has not been impressive enough this season.

"The Stormers props did reasonably well in the Super Rugby competition, until the last game [against the Crusaders in last week's semifinal]," the Bok coach said.

"Nobody talks about them anymore and they, the Stormers props, were all over the Cheetahs props when they played there [in Bloemfontein].

"So where does that leave us? Are we only going for a name, for sentimental reasons? Or do you want to take somebody who can add value to the team?."

Asked about who would be the back-up if Van der Linde, as expected, is ruled out on Monday.

"I am not a fortune teller, I can see that far into the future," he quipped.

"Let's see what happens on Monday and then revisit that question."

De Villiers said the tour squad should include 28 players, but they named just 27 on Friday - leaving a spot open for another prop, which at this stage is Van der Linde.

Injuries has robbed the Boks of many of their experienced campaigners and De Villiers said the matter of losing leaders in the squad had been addressed.

"It's something we've paid a great deal of attention to and we've made sure that those who we'll have as leaders will know what to do.

"John Smit is the captain but on the field the leaders will look after various aspects of our game."

By Jan de Koning