Bavuma, 24, is next in line if South Africa continue a policy of seven batsmen and four specialist bowlers.
A vacancy for another batsman was created by an injury to wicketkeeper-batsman Quinton de Kock which led to AB de Villiers keeping wicket in Centurion, a role which he is set to continue.
In almost 23 years of Test cricket since a united cricket board was admitted to the International Cricket Council in 1991, cricket officials have been embarrassed by the scarcity of Test-quality players from South Africa's largest racial group.
Next best is Monde Zondeki, who played in six Tests, while Lonwabo Tsotsobe played in five and Mfuneko Ngam and Thami Tsolekile in three each. If Bavuma plays on Friday he will become the first black specialist batsman to make the grade.
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At its annual meeting earlier this year, Cricket South Africa identified racial transformation as a high priority and all franchise teams were required to field at least two black Africans in all games.
Neither was expected to play but while Rabada was released to play for his franchise during the first Test, Bavuma was kept on, effectively as 13th man. He fielded throughout both West Indian innings, held two catches and impressed with his liveliness around the field.
Cape Town-born Bavuma went to St Davids, a leading cricket school in Johannesburg, and played for South African Schools and South Africa Under-19 during the 2008/09 season.
He has made steady progress since making his first-class debut in the same season and has scored 3631 runs in first-class cricket at an average of 35.95.