Nathan Redmond is expected to miss Sunday's Premier League clash with Tottenham due to an ankle ligament injury.
Saints winger Redmond suffered the problem during Wednesday evening's 2-0 Carabao Cup loss at home to Championship club Brentford.
Midfielder Stuart Armstrong could return to Ralph Hasenhuttl's squad having resumed training following a thigh injury, while summer signing Mohammed Salisu is building fitness as he awaits his Saints debut.
Tottenham will assess their squad after their gruelling Europa League trip to Bulgaria on Thursday night.
Jose Mourinho should be able to freshen things up if he needs to after leaving eight players at home, with Dele Alli and Toby Alderweireld among those who did not travel.
Japhet Tanganga is out with a thigh injury, but Serge Aurier will hope to shake off a training knock.
Southampton provisional squad: McCarthy, Forster, Gunn, Walker-Peters, Stephens, Bednarek, Vestergaard, Vokins, Bertrand, Romeu, Ward-Prowse, Smallbone, Tella, Djenepo, Ings, Adams, Long, Obafemi.
Tottenham provisional squad: Lloris, Hart, Gazzaniga, Doherty, Aurier, Alderweireld, Dier, Sanchez, Davies, Sessegnon, Winks, Sissoko, Hojbjerg, Lo Celso, Ndombele, Alli, White, Lamela, Bergwign, Moura, Kane
