The trio have recovered from knee, shoulder and groin injuries respectively and have all trained with the rest of the Wallaby squad in the early part of this week.
"We needed to be absolutely certain that they were right, because the South Africans are going to be the most physical opponent we have played so far," said Deans, who has led his side to wins over Ireland and France (twice) this summer.
"They're all looking good and ready to go again. By allowing them all time, we're happy that they are at the level, both physically and mentally, that they need to be to play."
Six of the players named in Deans' first Tri Nations squad will be taking on South Africa for the first time. Inside centre Berrick Barnes, halfback Luke Burgess, lock James Horwill, wing Peter Hynes and replacements Ryan Cross and Tatafu Polota-Nau will be in no doubt as to what to expect from the World Champions, however, as Deans has made his respect for the Springboks clear to his squad and to the media.
"Their record speaks for itself," said Deans.
"Historically, playing South Africa has always been a massive challenge, and recent events have probably only added to the significance of this assignment, but it's one that we're excited about as a group and looking forward to."
Australia (vs South Africa, Saturday, July 19, Perth, kick off 11.05 BST)
15 Adam Ashley-Cooper
14 Peter Hynes
13 Stirling Mortlock
12 Berrick Barnes
11 Lote Tuqiri
10 Matt Giteau
9 Luke Burgess
1 Benn Robinson
2 Stephen Moore
3 Al Baxter
4 James Horwill
5 Nathan Sharpe
6 Rocky Elsom
7 George Smith
8 Wycliff Palu
Replacements
16 Tatafu Polota-Nau
17 Matt Dunning
18 Hugh McMeniman
19 Phil Waugh
20 Sam Cordingley
21 Ryan Cross
22 Drew Mitchell
Springbok coach Peter de Villiers will announce his side for their third successive away match in this year's competition on Thursday (Australian time).
