The Gunners star, who makes his 150th appearance for the club and 100th Premier League start, was last selected for a league match in the 4-0 defeat to Liverpool at Anfield last month havingfound himself on the bench for the subsequent two league games.
Mesut Ozil has been in full training this week following a minor knee injury with Arsene Wenger naming the German international as a sub alongside Jack Wilshere and Theo Walcott.
Aaron Ramsey plays in the 'no.10' role while Mohamed Elneny partners Granit Xhaka in midfield.
West Brom boast former Arsenal left-back Kieran Gibbs in their starting XI just two months after he joined the Baggies in a permanent deal.
Tony Pulis's side are captained by Gareth Barry, who breaks Ryan Giggs's Premier League appearance record in the process.
Arsenal XI: Cech, Koscielny, Mustafi, Monreal, Bellerin, Elneny, Xhaka, Kolasinac, Ramsey, Alexis, Lacazette
Subs: Ospina, Mertesacker, Maitland-Niles, Wilshere, Ozil, Walcott, Giroud.
West Brom XI: Foster, Nyom, Gibbs, Robson-Kanu, Evans, Livermore, Barry, Rodriguez, Krychowiak, Dawson, Hegazi
Subs: Myhill, Yacob, Morrison, Rondon, Phillips, Brunt, McClean.