Pep Guardiola will be without the services of influential midfielder Fernandinho for a while after the Brazilian limped off against Porto on Wednesday.
Fernandinho was introduced in the 85th minute in the Champions League fixture, but was only on the pitch for six minutes before being withdrawn.
Ahead of that match, Nathan Ake picked an injury and was forced out, joining fellow defender Aymeric Laporte on the shelf.
More positive news for Guardiola is that Laporte and maverick playmaker Kevin De Bruyne will return to training before the game against the Hammers, which could put them into contention to play.
However, it is believed that Laporte has a better chance of featuring than De Bruyne.
Gabriel Jesus and Benjamin Mendy probably won't feature again until after the next international break.
Against Arsenal, Guardiola deployed a 3-4-3 formation in a match which they won before reverting back to a 4-3-3 against Porto. Joao Cancelo could again be asked to play left-back with Kyle Walker on the right if the back four remains.
Phil Foden came on to earn an assist versus Porto, and could potentially replace Bernardo Silva, who didn't have the best night against the Portuguese side.