Australian allrounder Cameron Green on Wednesday was ruled out of the third Sydney Test against South Africa with a fractured finger, and he will not bowl again in Melbourne.

The 23-year-old took a nasty rap on his finger from fast bowler Anrich Nortje while batting on day two of the second Test at the Melbourne Cricket Ground on Tuesday.

He retired hurt and went for scans.

"Cameron Green has a small fracture on his right index finger," Cricket Australia said.

"He will bat again in this match but will not bowl, followed by a period of recovery leading into the tour of India (in February).

It means Green -- the second-most expensive buy at the recent Indian Premier League auction -- will miss the third and final Test against the Proteas next week.

His inability to bowl in South Africa's second innings in Melbourne is a big blow, having taken a career-best 5-27 in their first innings' 189.

The hosts will resume day three on 386-3 in reply.

Australia is also sweating on pace spearhead Mitchell Starc, who hurt a finger as well on Monday.

If he is unavailable for the rest of the Melbourne Test, Australia will be down to just three fit bowlers -- captain Pat Cummins, fellow paceman Scott Boland and spinner Nathan Lyon.