Arsenal will be without Lucas Torreira for Saturday's Premier League visit of West Ham.
The midfielder suffered a fractured ankle in the FA Cup win over Portsmouth last time out and will be sidelined for some time.
Kieran Tierney (shoulder) is back in contention but Sead Kolasinac (shoulder) is absent, as are Cedric Soares and Calum Chambers (both knee).
Tomas Soucek has made a rapid recovery from injury to be fit for West Ham.
The Czech midfielder suffered a hip injury against Liverpool a fortnight ago but is already back in contention.
Andriy Yarmolenko is back in training but not ready to return, while Ryan Fredericks and Jack Wilshere are still sidelined.
Provisional Arsenal squad: Leno, Martinez, Bellerin, Papastathopoulos, Luiz, Mustafi, Mari, Holding, Tierney, Saka, Maitland-Niles, Guendouzi, Xhaka, Willock, Ceballos, Ozil, Pepe, Nelson, Lacazette, Martinelli, Nketiah, Aubameyang.
West Ham provisional squad: Fabianski, Ngakia, Diop, Ogbonna, Cresswell, Rice, Noble, Fornals, Bowen, Antonio, Haller, Randolph, Zabaleta, Balbuena, Masuaku, Snodgrass, Soucek, Lanzini, Anderson.
