Paine bats on despite fractured thumb

Australia captain Tim Paine has suffered a hairline fracture on his right thumb after copping a painful blow during play on day two, the Australian camp has confirmed this morning.

The wicketkeeper-batsman will resume his innings on five when play begins on day three and continue to play in the game 'as planned'.

Paine was hit while keeping up to stumps to Chadd Sayers in Johannesburg on Saturday, having misread a delivery that reared off the deck and beat the outside edge of Quinton de Kock's bat.

The Tasmanian was in obvious discomfort but waited until the end of the over before being assessed by team physio David Beakley.

Paine appeared to take a couple of painkillers before Beakley cleared him to stay on.

Beakley and team doctor Richard Saw went out during the morning drinks break to check on Paine's sore digit, which it's understood was also sore at the end of day one.

But Paine didn't even remove his gloves during the discussion with Beakley and Saw, confident he could carry on keeping.

Australia, in the midst of a leadership crisis following the sackings of Steve Smith and David Warner, opted against naming a vice-captain for the series finale at the Wanderers.

The nation's 46th Test captain has already implemented changes to the team's in-your-face approach, having stopped their sledging and introduced a pre-game handshake with the Proteas on Friday.

It's not unusual for a keeper to break through the pain barrier and end their careers with mangled hands but Paine's history means there's always a sense of unease whenever he's struck on the right hand.

The 33-year-old's right index finger was broken after being struck by a 148.2km/h thunderbolt from Dirk Nannes in a 2010 exhibition game.

The recurring injury required seven rounds of surgery and almost ended Paine's career.

He still has eight pins, a metal plate and a piece of hip bone in the finger that rarely feels right when he's keeping.

"Because of the way I catch, if I go fingers up it pretty much hits right on it. It hurts for a little bit and then it goes away," Paine said after his shock Ashes call-up last November.

"If I go to hit the ball really hard and I toe it, it tends to rattle it a little bit."

Qantas tour of South Africa

South Africa squad: Faf du Plessis (c), Hashim Amla, Temba Bavuma, Theunis de Bruyn, Dean Elgar, Heinrich Klaasen, Quinton de Kock, Keshav Maharaj, Aiden Markram, Morne Morkel, Chris Morris, Wiaan Mulder, Lungi Ngidi, Duanne Olivier, Vernon Philander, Kagiso Rabada, AB de Villiers.

Australia squad: Tim Paine (c), Joe Burns, Pat Cummins, Peter Handscomb, Josh Hazlewood, Jon Holland, Usman Khawaja, Nathan Lyon, Mitchell Marsh, Shaun Marsh, Glenn Maxwell, Matt Renshaw, Jhye Richardson, Chadd Sayers, Mitchell Starc.

Warm-up match: Australia beat South Africa A by five wickets. Report, highlights

First Test Australia won by 118 runs. Scorecard

Second Test South Africa won by six wickets. Scorecard

Third Test South Africa won by 322 runs. Scorecard

Fourth Test Wanderers, Johannesburg, March 30-April 3. Live coverage