With Aaron Ramsey ruled out with a groin strain, England international Walcott takes his place on the right side of the front three.
Koscielny, meanwhile, comes in at the heart of the defence, with Thomas Vermaelen moving to left back in place of Andre Santos.
James Shea is on the bench in place of Damian Martinez, along with Johan Djourou.
Team in full: Mannone, Sagna, Mertesacker, Koscielny, Vermaelen, Arteta, Wilshere, Cazorla, Podolski, Walcott, Giroud.
Subs: Shea, Santos, Djourou, Jenkinson, Coquelin, Arshavin, Chamakh.Copyright 2015 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 6 Nov 2012