Burger was injured in his Western Province team's loss to Sharks
Experienced flanker Schalk Burger and young centre Juan de Jongh have been ruled out of South Africa's tour of Britain and Ireland with injuries.
Both players suffered knocks during Saturday's Currie Cup final.
Burger, 27, capped 63 times, has a broken rib, while De Jongh, 22, who has six Springboks caps to date, has a hairline fracture to his left ankle.
South Africa face Ireland in Dublin on Saturday, followed by Tests against Wales, England and Scotland.
Centre Adrian Jacobs has now been added to the squad, with Jean de Villiers also struggling with a groin problem.
Burger's place goes to the Bulls forward Deon Stegmann, bringing the number of uncapped players to seven.
Another player from the Pretoria franchise, full-back Zane Kirchner, has also been added to the 30-man squad following the withdrawal of scrum-half Ricky Januarie.
Springboks Coach Peter de Villiers said: "It's a blow to lose players but we've rolled with the punch and already moved on.
"It's not an ideal situation but we've all got on with our jobs and are focused only on the players that we have in camp."
Flanker Willem Alberts (calf), hooker Chiliboy Ralepelle (flu) and centre De Villiers all took no part in either of the two field sessions earlier on Monday.
The spate of injuries means the team announcement for Saturday's Test at the Aviva Stadium has now been delayed until Thursday.
De Villiers added: "We'll give the players some more time in rehab before we confirm the team."
The latest withdrawals take to 13 the number of senior players who have been forced out of the tour by injury.
The others that are unfit are captain John Smit, Jaque Fourie, Wynand Olivier, Andries Bekker, Fourie du Preez, Heinrich Brussow, JP Pietersen, Gurthro Steenkamp, Butch James and BJ Botha.