Injured Kolbe leaves Springbok camp with knee 'niggle'
The 30-year-old was injured while playing for his Japanese club Tokyo Sungoliath.
Kolbe, who was named among 35 players for the Boks' first training camp of the year, joined his team-mates on Sunday evening but was released on Monday "to examine the extent of niggle which he picked up during his regular Japanese club season".
He has been replaced in the camp by uncapped Bulls back-row forward Celimpilo Gumede.
"Celimpilo has been playing impressive rugby this season and we are excited to see how he integrates in the squad and what he has to offer at training," said Springbok head coach Rassie Erasmus.
South Africa face Wales at Twickenham on June 22 before going into a busy schedule that includes two Tests against Ireland and one against Portugal before they embark on the Rugby Championship, which involves six matches against Australia, arch-rivals New Zealand and Argentina in August and September.
The four-time world champions then take on Scotland, England and Wales during a November tour of Europe.