"The Emerging Springboks represent the perfect opportunity for the squad to put the first Test behind them and to create a focus for the second Test on Saturday."
Commenting on the team selection, head coach Ian McGeechan said: "There were many positives that came out of the Test match on Saturday.
"The Emerging Springboks match, and our training this week, will allow us to build on these plus address areas we know we need to improve on.
"There is still a lot to play for and the players are well aware of that.
"The mood in camp is still very positive due to the fact that we did come very close to winning on Saturday and the fact that we created so many scoring opportunities.
"The players are well aware of the importance of the match tomorrow against the Emerging Springboks.
"We need to step up our performance against a talented outfit whose players, like ours, will be determined to show that they are worthy of a Test place. It should be a great match."
He added: "The two latest squad members, Tim Payne and John Hayes, will start against the Emerging Springboks to give them immediate field time.
"This is important in terms of the balance of the squad as three of our other props played in the Test match only two days ago and Andrew Sheridan is recovering from injury.
"Ronan O'Gara will lead the team against the Emerging Springboks which is a well deserved honour for a senior player who has served Munster, Ireland and the British & Irish Lions with distinction."
O'Gara is the fourth member of Ireland's 2009 Grand Slam-winning side to captain the Lions in South Africa, following in the footsteps of Brian O'Driscoll, Donncha O'Callaghan and tour captain Paul O'Connell.
McGeechan's squad for the Emerging Springboks game includes six players who saw action in the first Test defeat to South Africa - O'Callaghan, Martyn Williams, Lee Mears, Phil Vickery, David Wallace and Ugo Monye.
BRITISH & IRISH LIONS TEAM/REPLACEMENTS (v Emerging Springboks, 2009 Lions Tour, Tuesday, June 23, Newlands, kick-off 7.10pm local time/6.10pm Irish time):
15. Keith Earls (Munster/Ireland)
14. Shane Williams (Ospreys/Wales)
13. Riki Flutey (London Wasps/England)
12. Gordon D'Arcy (Leinster/Ireland)
10. Ronan O'Gara (Munster/Ireland) (capt)
9. Harry Ellis (Leicester Tigers/England)
1. Tim Payne (London Wasps/England)
2. Ross Ford (Edinburgh/Scotland)
3. John Hayes (Munster/Ireland)
4. Donncha O'Callaghan (Munster/Ireland)
5. Nathan Hines (Perpignan/Scotland)
6. Joe Worsley (London Wasps/England)
7. Martyn Williams (Cardiff Blues/Wales)
8. Andy Powell (Cardiff Blues/Wales)
16. Lee Mears (Bath/England)
17. Phil Vickery (London Wasps/England)
18. Simon Shaw (London Wasps/England)
19. David Wallace (Munster/Ireland)
20. Mike Blair (Edinburgh/Scotland)
21. James Hook (Ospreys/Wales)
22. Ugo Monye (Harlequins/England)