The 27-year-old completed his £7 million move to the European champions on Friday, in time to start the cup clash at St. Mary’s Stadium.
Elsewhere, Ross Turnbull continues in goal with Petr Cech still sidelined with a groin injury. Juan Mata and Eden Hazard are restored to the starting line-up in two of six changes by Rafael Benitez following the shock 1-0 home loss to QPR, with Frank Lampard, Fernando Torres and Oscar all on the bench. Ashley Cole is handed the captain's armband.
Nigel Adkins makes just two changes from the team who were unfortunate to gain just a point from Arsenal last time out, with Jay Rodriguez and James Ward-Prowse coming in for Gaston Ramirez and Rickie Lambert.Southampton starting XI: Boruc; Cork, Fonte, Yoshida, Shaw; Guly, Schneiderlin, S. Davis, Ward-Prowse, Puncheon; Rodriguez,
Subs: K. Davis, Hooiveld, Reeves, De Ridder, Lee, Lambert, Mayuka
Chelsea starting XI: Turnbull; Azpilicueta, Ivanovic, Cahill, Cole; Ramires, Luiz; Moses, Mata, Hazard; Ba.
Subs: Hilario, Ferreira, Bertrand, Lampard, Oscar, Marin, Torres