The Welsh influence is evidenced in the choice of Shane Williams for the number 22 jersey ahead of Keith Earls who had a fine game against the Emerging Boks and also offers cover at centre wing and full back should it be needed.
O'Callaghan could be excused for wondering what exactly he has done wrong while his colleague Ronan O'Gara must be wondering what he has to do to get a start ahead of the thus far less than convincing Stephen Jones.
One of the problems the Lions will face on Saturday is the question having to play at 1400m above sea level. And to that end Ian McGeechan has opted to keep the squad in Cape Town planning to arrive in Pretoria late tomorrow afternoon.
Former Bok flyhalf Joel Stransky recently said McGeechan had got his planning horribly wrong, considering the final two Tests are at altitude. "He should have based the Lions up country and popped down to the coast for matches; they've chartered their own plane so it wouldn't have been an issue."
Lions: Robert Kearney, Tommy Bowe, Brian O'Driscoll, Jamie Roberts, Luke Fitzgerald, Stephen Jones, Mike Phillips, Gethin Jenkins, Matthew Rees, Adam Jones, Simon Shaw, Paul O'Connell capt; Tom Croft, David Wallace, Jamie Heaslip. Replacements: Ross Ford, Andrew Sheridan, Alun Wyn Jones, Martyn Williams, Harry Ellis, Ronan O'Gara, Shane Williams.
South Africa: Francois Steyn; JP Pietersen, Adi Jacobs, Jean de Villiers, Bryan Habana; Ruan Pienaar, Fourie du Preez; Tendai Mtawarira, Bismarck du Plessis, John Smit; Bakkies Botha, Victor Matfield; Schalk Burger, Juan Smith, Pierre Spies. Replacements: Chiliboy Ralepelle, Deon Carstens, Andries Bekker, Danie Rossouw, Heinrich Brussow, Jaque Fourie, Morne Steyn.