The assured performances of Australia's two newest Test team inclusions, Shaun Marsh and Alex Doolan, has meant there will almost certainly not be a vacancy for him to play in the second Test at Port Elizabeth starting on Thursday, nor the final Test at Cape Town starting on March 1.

Hughes' prospects of selection as part of the squad of 16, one more than Australia's original squad allocation, are further hindered by Watson being clearly ahead of him in the selection pecking order.

All-rounder Watson is recuperating from a calf injury he suffered just over a fortnight ago. He batted in the Centurion Park indoor nets during the first Test and walked laps of the arena before play.

Hughes last played a competitive red-ball match in early December, finishing the first half of the Sheffield Shield season with a century in each of the last two matches before the hiatus for the Big Bash League.

The unorthodox but prolific left-hander was the most contentious exclusion from Australia's original 15-man squad for its series in South Africa. In the aftermath of that decision, which angered South Australian officials, the disappointed 25-year-old was excused by state selectors from a Futures League match in January. South Africa-bound Chris Rogers instead played for the Redbacks in that game, as part of his preparation for the tour.

Hughes eventually won selection in the Test squad after selectors ruled out Marsh due to injury. He top-scored with 83 in Australia's only practice match, on February 7. A day later, however, fit-again Marsh was summoned to South Africa and was selected ahead of Hughes for the series-opener in Centurion. Marsh and debutant Doolan scored 308 runs between them in the thrashing to buttress their positions in the team.

South Australia's next shield match, at home to Victoria, begins on Thursday. While the Redbacks would be eager to regain their dominant opener Australian are unlikely to allow that while Watson's capability for selection is uncertain.

The Australian team will fly to Port Elizabeth on Monday afternoon and will not train until Tuesday. Its hierarchy is highly unlikely to make a decision at the end of that session, because it wants Watson to prove his fitness over multiple sessions before it clears him to return. Until that point Hughes looks set to be stay in South Africa on the fringes of the squad.

Hughes' best chance of playing again as soon as possible would appear to be if selectors release him from the squad closer to the start of the third Test on March 1, with enough time for him to return to the Redbacks for the day-night round of the shield starting on March 3. Failing that, the last round of the Shield begins on February 11.

Captain Michael Clarke is no longer a selector, but last week he expressed a preference for whichever specialist batsman missed selection in Centurion - Hughes - to be retained in the squad.

"That'll be a decision for the coach and the other selectors, but in my opinion once you're on tour you're on tour. It's not like it's a three-hour flight back to Australia. It's a long way," Clarke said.

"I think all the players have found it's taken a bit longer than we expected to get over jet lag, so I'd be surprised. But if they think that's in the best interests of getting guys right for the second Test and third Test then they'll make that decision. I'll live with whatever decision in made."