Chelsea have drawn their last two Premier League matches.
Southampton, meanwhile, are without victory in three fixtures.
Southampton striker Shane Long (toe) and midfielder Mohamed Elyounoussi (minor injury) returned to training this week and are available for selection.
There are no other injuries reported by manager Mark Hughes.
Similarly, Chelsea's Maurizio Sarri has no injury concerns.
Chelsea head coach Maurizio Sarri could become the sixth manager to remain unbeaten in his first eight Premier League matches. The previous five are Frank Clark, who was unbeaten in his first 11 PL matches for Nottingham Forest, and four managers on eight matches: John Lyall (Ipswich Town), Peter Taylor (Leicester City), Jose Mourinho and Felipe Scolari (both Chelsea).
The Blues have only one defeat at St Mary's in 11 matches there in all competitions, winning the last three.
Olivier Giroud is one match from his 200th in the competition and enjoys facing Southampton. The Frenchman has scored in each of his past four matches against them, netting five goals in total.
Mark Hughes has lost his last six matches to Chelsea as a manager.
Referee: Craig Pawson
Assistants: Ian Hussin, Richard West
Fourth official: Roger East