The 19-year-old Pretorius and 22-year-old Brevis will bat in the middle-order while seamer bowler Yusuf will form part of an inexperienced pace attack that includes Kwena Maphaka and Corbin Bosch, who have both only played one Test apiece.
The Proteas have rested a host of senior players for the two-match Test series against their African neighbours following their victory in the World Test Championship final with Kagiso Rabada, Aiden Markram, Ryan Rickelton, Tristan Stubbs and Marco Jansen all missing.
Regular skipper Temba Bavuma has been ruled out of the tour with a hamstring strain while paceman Lungi Ngidi will only join the squad ahead of the second Test.
Pretorius has only played seven First-Class matches but has scored three centuries and a fifty in the red-ball format after a breakout domestic campaign last home summer.
Brevis has previously been in the Test squad, on tour in Bangladesh last season, but will make his debut in the longest format with an average of more than 41 in 20 First-Class matches that includes four hundreds.
The 27-year-old Yusuf has been rewarded for showing some fine form for the Lions in last season's domestic 4-Day competition where the pacer took 23 wickets in six matches.
The right-arm quick also recently had a stint with Durham in English county cricket and largely impressed, taking 16 wickets in four games.
Tony De Zorzi will open the batting with Matthew Breetzke, who also just one Test cap, while all-rounder Wiaan Mulder will continue at number three as he did in the WTC final against Australia.
David Bedingham will slot in at number four ahead of the Pretorius and Brevis while Kyle Verreynne will take the wicketkeeper gloves and bat at number seven.
Bosch, skipper Maharaj, Yusuf and teenage fast bowler Maphaka complete the Proteas starting line-up for the first of two Test matches at the Queen's Sports Club.
Corbin Bosch picked up a maiden five-wicket haul as the Proteas wrapped up a mammoth 328-run victory in the second session of the fourth day of the first Test against Zimbabwe in Bulawayo.
Wiaan Mulder hit a career-best 147 as the Proteas were bowled out for 369 in the second innings to set Zimbabwe a mammoth target of 537 with two days remaining of the first Test in Bulawayo.
Lhuan-dre Pretorius became the youngest player to score a Test century for the Proteas to help the visitors recover from 55-4 to post 418-9 at stumps on day one against Zimbabwe in Bulawayo.
Teenage fast bowler Kwena Maphaka will lead the Proteas bowling attack in the first Test against Zimbabwe that starts in Bulawayo on Saturday, head coach Shukri Conrad has said.
