Alex is expected to deputise for suspended Chelsea captain John Terry in the Champions League quarter-final return leg against Liverpool.
Terry misses out at Stamford Bridge after collecting a yellow card for his challenge on Liverpool goalkeeper Pepe Reina at Anfield.
Right-back Jose Bosingwa is expected to be sidelined because of hamstring trouble while Brazilian Alex will replace Terry alongside Ricardo Carvalho in the centre of the defence.
Didier Drogba - scorer of seven goals in 10 games under Guus Hiddink - is again likely to be prefered to Nicolas Anelka as lone frontman.
Joe Cole and Paulo Ferreira are absent with knee ligament injuries.
Chelsea hold a 3-1 lead from last week's first leg.
Chelsea (from): Cech, Hilario, Belletti, Alex, Ivanovic, Carvalho, Mancienne, A Cole, Lampard, Ballack, Deco, Obi, Kalou, Essien, Malouda, Di Santo, Anelka, Quaresma, Stoch, Drogba.