Cape Town - Australia's Mitchell Starc is reportedly suffering from a calf injury ahead of the third Test against the Proteas in Cape Town.

With South Africa likely to go into the Test without their most dangerous bowler - Kagiso Rabada is suspended unless an appeal proves otherwise - Australia are now also at risk of losing their biggest bowling weapon. 

According to Cricinfo, Starc sat out of training on Monday having already had a week off, and he will now be given until the end of Tuesday to prove his fitness ahead of the third Test, which gets underway at Newlands on Thursday. 

Starc is instrumental to the Australian cause, and his devastating match figures of 9/109 went a long way towards securing the first Test for the visitors in Durban. 

Should Starc be declared unfit and unavailable, Australia can turn to one of Jhye Richardson or Jackson Bird. 

The series is currently tied at 1-1 with two Tests to play.