The Armenia international completed his move from Manchester United last week, and has been named in Arsenal's matchday squad for the first time but doesn't start due to a lack of match fitness.
The 31-year-old is expected to complete his move to the Blues on Transfer Deadline Day in a move which will help facilitate Pierre-Emerick Aubameyang's long awaited move to Arsenal.
Jack Wilshere misses out with an illness after starting the last eight league matches for Arsenal.
Arsenal XI: Cech, Bellerin, Mustafi, Koscielny, Monreal, Elneny, Xhaka, Ramsey, Iwobi, Ozil, Lacazette
Subs: Ospina, Chambers, Kolasinac, Maitland-Niles, Mkhitaryan, Nketiah, Giroud