West Ham United's long injury list means that midfielder Cheikhou Kouyate has to play as an emergency centre-back in today's clash with Arsenal.
Enner Valencia misses out with a toe injury, but Alex Song has shaken off a knee problem to take his place in midfield.
Arsenal are without Alex Oxlade-Chamberlain, who faces a month on the sidelines with a hamstring injury.
Mathieu Flamini is fit again but has to settle for a place on the bench as Francis Coquelin keeps his place in midfield following his impressive run of form.
Arsenal: Ospina; Chambers, Mertesacker, Koscielny, Monreal; Coquelin, Ramsey, Walcott, Ozil, Sanchez; Giroud
West Ham United: Adrian; O'Brien, Collins, Kouyate, Cresswell; Song, Noble, Nolan, Jarvis, Downing; Sakho
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