Glenn McGrath [ Images ], Adam Gilchrist [ Images ] and Brett Lee [ Images ] have been left out of a 12-man Australian squad to play South Africa [ Images ] in a one-off Twenty20 [ Images ] international next week.

Australia's [ Images ] chairman of selectors Trevor Hohns said the trio were being rested to give them a short break between the Test series and triangular one-day series with South Africa and Sri Lanka [ Images ].

"Twenty20 cricket is still a bit of an unknown to us but we have tried to keep as much of the one-day squad together as possible," Hohns said in a statement.

"Having said that, Brett Lee, Glenn McGrath and Adam Gilchrist have not been selected in order to enable each of them to freshen up before the (one-day) series.

"Brett, Glenn and Adam have worked particularly hard during the Melbourne [ Images ] and Sydney [ Images ] Test matches and we want to manage each of their respective workloads carefully."

Hohns also announced that Mike Hussey [ Images ] had been promoted to vice-captain in the absence of Gilchrist, reflecting his growing importance in the team.

"He has done an excellent job in the one-day format and we have every confidence that he has the necessary ingredients to take on this additional responsibility," Hohns said.

The Twenty20 match will be played in Brisbane [ Images ] on January 9. The one-day series starts four days later.