The Lions have won all four of their opening tour fixtures and are now just a week away from the start of the three-match Test series against the world champion Springboks.
Cardiff Blues openside Martyn Williams returns from a shoulder injury to push his claims for a Test place, with club and international colleague Andy Powell looking for a strong performance at No8 following Jamie Heaslip's try-scoring efforts against the Sharks on Wednesday night.
There are two more Magners League players included in the pack, with Matthew Rees of the Scarlets starting at hooker and Munster lock Donncha O'Callaghan hoping to do enough to join Paul O'Connell in the second row in Durban next weekend.
In the backline, Leinster's Rob Kearney is named at full back, with Tommy Bowe of the Ospreys looking to build on his fine start to the tour having had 10 days without a match.
Keith Earls and Stephen Jones complete the league's starting contingent, while Ross Ford, Mike Blair, James Hook and Gordon D'Arcy will all hope to see some game time from the bench.
"The coaching staff is very pleased with the way the squad reacted to some bad injury news this week. The players took the news on the chin, trained well, focussed on the next match and the performance against the Sharks was excellent," said McGeechan.
"The squad is very close as a group of players but now there is now a competitive edge developing as we approach the Test series. That is how it should be.
"I reminded the players when I told them the team to play Western Province that we were not selecting the Test side until next Tuesday following the Southern Kings match.
"No starting players are backing up from the Sharks match as we continue our desire to see all players involved in at least two full matches prior to Test selection. Martyn Williams comes into the starting XV following his recovery from a shoulder knock and Riki Flutey gets his first starting role after proving his fitness off the bench against the Sharks."
Lions tour manager Gerald Davies said he was delighted his team had remained unbeaten over the first four games of the tour and is looking to extend that run into next week's Castle Series.
"As a tour party we are delighted that we have reached Cape Town and the final Saturday provincial match prior to the Test series with an unbeaten record. Team morale is high and each team that takes the field is determined to maintain the momentum and to fight for an individual Test place."
British & Irish Lions (vs Western Province)
15. Rob Kearney (Leinster/Ireland)
14. Tommy Bowe (Ospreys/Ireland)
13. Keith Earls (Munster/Ireland)
12. Riki Flutey (London Wasps/England)
11. Ugo Monye (Harlequins/England)
10. Stephen Jones (Scarlets/Wales)
9. Harry Ellis (Leicester Tigers/England)
8. Andy Powell (Cardiff Blues/Wales)
7. Martyn Williams (Cardiff Blues/Wales)
6. Joe Worsley (London Wasps/England)
5. Nathan Hines (Perpignan/Scotland)
4. Donncha O'Callaghan (Munster/Ireland)
3. Phil Vickery (London Wasps/England, captain)
2. Matthew Rees (Scarlets/Wales)
1. Andrew Sheridan (Sale Sharks/England)
Replacements
16. Ross Ford (Edinburgh/Scotland)
17. Euan Murray (Northampton Saints/Scotland)
18. Simon Shaw (London Wasps/England)
19. Tom Croft (Leicester Tigers/England)
20. Mike Blair (Edinburgh/Scotland)
21. James Hook (Ospreys/Wales)
22. Gordon D'Arcy (Leinster/Ireland)