Symonds had to miss Sunday's first game of the five-match series in Centurion due to a thigh strain, while injuries to captain Ricky Ponting (abdominal strain) and paceman Stuart Clark (bruised ribs) left Australia with just 11 fit players.
Cricket Australia announced yesterday that top-order batsman Phil Jaques would be flying to South Africa during the week to act as batting cover.
''We're not much closer to knowing who's going to be fit again for Friday,'' Errol Alcott, the Australian team's physiotherapist, admitted today.
Ponting took no part in the training session, while Clark said he would start bowling again on Thursday and hoped to be fit for Friday's match.
The South Africans, who won the opening game by six wickets, arrive in Cape Town tomorrow.