South Africa reduced its 2011 home series against Australia from three tests to two on Friday because of "time constraints," the latest sign that Twenty20 was threatening the five-day game as cricket's showpiece format.
For the first time, a tour involving the teams will feature as many T20 internationals as tests.
Cricket South Africa confirmed the schedule would consist of two tests, three one-day internationals and two Twenty20s in October and November.
The teams have always played three-test series since the Proteas' post-apartheid return to international cricket in 1991, but the advent of Twenty20 competitions like the money-spinning IPL, the Champions League Twenty20 and the International Cricket Council's World Twenty20 have contributed to a packed international calendar.
"Unfortunately time constraints prevent us from playing more than two tests against Australia this time around," CSA chief executive Gerald Majola said. "In this regard I would like to stress that test cricket remains in our view the ultimate pinnacle of the game.
"There is room for all three formats and they complement one another in an outstanding overall package."
Top South African and Australian players are involved in the ongoing IPL in India, which runs for seven weeks and came straight after the 50-over World Cup.
The Champions League is normally played in September or October and the World Twenty20 will be expanded from 12 to 16 teams in 2012.
A series between the teams was "something to be savored," Majola said, but a test has been sacrificed to shorten the tour. Majola added the plan was to play four tests against Australia on their next visit in 2014 to make up for the curtailed series.
The tests between No. 2-ranked South Africa and No. 5-ranked Australia are set for Nov. 9-13 in Cape Town and Nov. 17-21 in Johannesburg, following the T20 and ODI series. Australia is the top-ranked one-day team.
CSA also said South Africa would play Sri Lanka in three tests and five ODIs in December and January 2012, the first full tour to the country by the Sri Lankans since 2002.
South Africa will meet the World Cup finalist in a one-dayer at Paarl, near Cape Town - only the ninth ODI game ever at the ground and the first since the 2003 World Cup. Bizarrely, Sri Lanka has played three ODIs at the venue, while South Africa has played only two.
South Africa is without a coach or a one-day captain after Corrie van Zyl and Graeme Smith stepped down from their respective roles following the World Cup.
CSA will begin interviewing a list of candidates for the coaching role on May 16, with India's World Cup-winning boss Gary Kirsten believed to be the front-runner for the job. The new coach will be announced in June.
The Proteas will complete their summer season with a tour of New Zealand, CSA said.