South Africa's JP Duminy has ruptured his Achilles and faces six months out of the game.
Duminy was taken to hospital after picking up an injury during fitness drills in the warm-down after stumps on day one of the first Test.
South Africa team manager Dr Mohammed Moosajee said: "At first assessment JP said he heard a loud clicking sound and it felt like he had been hit by an object.
"The diagnosis of an Achilles tendon rupture was confirmed by the MRI scan this evening and he will undergo surgery to re-attach the tendon on Saturday morning.
"Injuries of this nature are caused by a sudden contraction against the direction of movement by the calf muscle as was the case during his sprint.
"We will only be able to gauge further down the line on an expected recovery date, but injuries of this nature have been known to take up to six months before the player can resume playing cricket.
"He is obviously disappointed, but JP, being JP, is trying his best to stay positive, he says everything happens for a reason.''
The Proteas had enjoyed day one of the first Test against Australia, reaching 255 for two.
South Africa are due to name a replacement on Monday. During the ongoing match, the Proteas' 12th man Francois du Plessis will field in Duminy's place but will not be able to bat.