The pair are both still troubled by the muscular injuries that kept them out of the midweek Champions League clash with RB Leipzig.
Striker Shane Long will be available for Southampton after completing his isolation following a positive Covid-19 test.
Midfielder Will Smallbone is back in full team training after eight months on the sidelines with a serious knee injury but is not expected to be rushed back into match action.
Winger Theo Walcott and midfielder Stuart Armstrong are still sidelined with calf muscle issues.
Man City provisional squad: Ederson, Carson, Slicker, Walker, Cancelo, Zinchenko, Dias, Ake, Fernandinho, Gundogan, Rodri, De Bruyne, Silva, Sterling, Foden, Mahrez, Grealish, Jesus, Torres, Palmer.
Southampton provisional squad: McCarthy, Stephens, Perraud, Livramento, Salisu, Romeu, Ward-Prowse, Redmond, Djenepo, Elyounoussi, A Armstrong, Forster, Walker-Peters, Lyanco, Bednarek, Valery, Tella, Diallo, Adams, Broja, Long.