South Africa added forwards Ashley Johnson and Ryan Kankowski to a constantly changing squad Monday amid injury and illness concerns ahead of Tri-Nations Tests against Australia and New Zealand.

It was the second revision in as many days to the original 24-man group after flank Heinrich Brussow was called up Sunday to increase the back-row options for coach Peter de Villiers.

Johnson, from the Cheetahs, can play flanker or No.8 while Kankowski of the Sharks is a specialist No.8 and both toured Australasia last month when the Springboks lost heavily to the Wallabies and All Blacks.

The call-ups came because utility forward Danie Rossouw suffered gastroenteritis while number eight Pierre Spies is battling to overcome a groin injury and did not train Monday in this Indian Ocean city.

Back-row injuries are a major concern for De Villiers ahead of Tests against Australia on August 13 at Kings Park in Durban and defending Tri-Nations champions New Zealand one week later at Nelson Mandela Bay Stadium in Port Elizabeth.

Schalk Burger, Juan Smith, Willem Alberts and Duane Vermeulen have been ruled out of the home leg of the southern hemisphere championship, which offers South Africa a final chance of match practice before the Rugby World Cup kicks off.

Revised Springbok squad

Backs: Gio Aplon, Francois Steyn, JP Pietersen, Bryan Habana, Jaque Fourie, Juan de Jongh, Jean de Villiers, Morne Steyn, Butch James, Ruan Pienaar, Fourie du Preez, Francois Hougaard. Forwards: Ryan Kankowski, Ashley Johnson, Pierre Spies, Jean Deysel, Heinrich Brussow, Danie Rossouw, Bakkies Botha, Victor Matfield, Gerhard Mostert, John Smit (capt), Bismarck du Plessis, Tendai 'Beast' Mtawarira, Jannie du Plessis, Gurthro Steenkamp, CJ van der Linde.

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