Alex will start on the bench at Stamford Bridge after recovering from knee surgery.
The Brazil defender is hoping to make his first appearance since November and his return gives Carlo Ancelotti a full squad to choose from, with David Luiz also available after being cup-tied in Wednesday night's Champions League defeat to Manchester United.
Wigan captain Gary Caldwell is available for Roberto Mancini's side after emergency dental work this week.
The Scotland defender required treatment to repair three teeth after a collision with Tottenham's Roman Pavlyuchenko last Saturday.
His availability means the bottom side are at full strength for the daunting encounter at Stamford Bridge.
New signing Connor Sammon is pushing for a first start after three substitute appearances while Mohamed Diame will hope to regain a midfield place.
Chelsea (from): Cech, Bosingwa, Ferreira, Terry, Luiz, Ivanovic, Alex, Zhirkov, Cole, Mikel, Essien, Lampard, Ramires, Benayoun, Kalou, Malouda, Anelka, Torres, Drogba, Turnbull.
Wigan (from): Al Habsi, G Caldwell, Gohouri, Figueroa, Alcaraz, Watson, N'Zogbia, Diame, Moses, McCarthy, Rodallega, Stam, Lopez, Thomas, Gomez, McArthur, McManaman, Cleverley, S Caldwell, Sammon, Di Santo, Boyce, Thomas, Pollitt, Kirkland.