A day after all-rounder James Faulkner was scratched and replaced by Moises Henriques as a result of a knee injury, Marsh remained in Perth for treatment on Wednesday as Michael Clarke's men departed for Johannesburg without him.

A final decision on the 30-year-old was yet to be announced - his likely replacement would be Phillip Hughes - but within the Australian camp it has all but been conceded that he will not be available to make his return to Test cricket in South Africa.

Marsh's history of back and hamstring injuries does not count in his favour, and with only a week until Australia's one and only pre-series warm-up match in Potchefstroom, time has not been on his side.

Clarke said he wanted to have all players fit and available for that game before the first Test in Centurion, starting on February 12, and while back-up fast bowler Jackson Bird was tipped to join the tour party after wrestling with a sore back, Marsh's chances dimmed. Barring an unexpected and last-minute recovery, he won't be on his way over the Indian Ocean.

Whether the West Australian would have been a genuine contender to reclaim a position in the Test top order in any case was unclear as Clarke nominated Shane Watson to stay in the key No.3 slot.

"I know he wants to bat there, he loves that extra responsibility," Clarke said of Watson. "I know we've got options in Alex Doolan and Shaun Marsh; they could both bat at three and have done in their careers for their states, and Shaun has batted at No.3 for Australia.

"But I think Watto's experience [puts him in front] and he's played pretty well for us, to be honest.

"I know he's copped a little bit of criticism that he hasn't made as many runs as he would have liked in the first innings, but who has? We'd all like a few more runs, that's for sure.

"Right now I'm backing Watto to have a fantastic series and lead by example. He's played a lot of cricket, and he's a senior member of our team, and No.3 is an important role."

Australia arrive in South Africa with a fine record on the continent, not having lost a Test series there against the Proteas since they were readmitted to international competition in 1992.

However, Clarke's team has struggled against major nations away from home - their last win on the road against either South Africa, England or India was in November 2011 at the Wanderers, a match in which a teenage Pat Cummins starred - and even in the afterglow of an historic Ashes summer a clash against the world No.1 team shapes as a real test.

Clarke said the retired Jacques Kallis would be "irreplaceable" for South Africa but after the ordeals in India and England last year, winning in foreign lands is the ultimate challenge.

"A lot of teams in Test cricket are having success in their own backyard, but the greatest challenge is to be able to win away from home, so that's what we face right now," Clarke said.

"We're playing against a very good opposition ... wicket-wise, temperature-wise and country-wise there's a lot of similarities, so that'll help us become accustomed to conditions. But when you're playing in front of your home fans we've seen the benefit of that this summer, and that's obviously going to help South Africa. We've got to be on top of our game."

Meanwhile, South Africa have named a 15-man squad for the series against Australia, moving into the post-Jacques Kallis era with the inclusion of all-rounders Wayne Parnell and Ryan McLaren and throwing their weight behind seam bowling with the omission of leg-spinner Imran Tahir.

The Proteas are without the champion Kallis, who retired after their previous Test series against India in December, but expect wicketkeeper/batsman AB de Villiers to be on deck after recovering from hand surgery.

"We want to stay constant to the brand of cricket we have played over the last few years that has brought us such success," said Proteas selector Andrew Hudson.

South Africa squad: Graeme Smith (capt), Hashim Amla, AB de Villiers, JP Duminy, Faf du Plessis, Dean Elgar, Rory Kleinveldt, Ryan McLaren, Morne Morkel, Wayne Parnell, Alviro Petersen, Robbie Peterson, Vernon Philander, Dale Steyn, Thami Tsolekile.