Joe Mourinho has made three changes to his Chelsea team from Boxing Day's 2-0 win over West Ham for today's trip to Southampton, bringing in Filipe Luis, John Obi Mikel and Andre Schurrle.
Cesar Azpilcueta, Willian and Oscar all miss out.
For fourth-placed Southampton, manager Ronald Koeman has made four changes to the team who beat Crystal Palace 3-1 on Boxing Day.
The Blues are currently three points ahead of second-placed Manchester City, who travel to Burnley today.
Southampton: Forster, Yoshida, Fonte, Alderweireld, Targett, Wanyama, Schneiderlin, S. Davis, Tadić, Mané, Pellè.
Subs: K. Davis (GK), Gardos, Long, Ward-Prowse, Isgrove, Reed, McCarthy.
Chelsea: Courtois, Ivanovic, Cahill, Terry, Filipe Luis, Matic, Mikel, Schurrle, Fabregas, Hazard, Diego Costa.
Subs: Cech, Zouma, Azpilicueta, Ramires, Willian, Remy, Drogba.