In contrast, Basel could end Wednesday evening in second place if they claim all three points. To achieve that feat, they would also need Chelsea's encounter with Schalke 04 to end in a victory, rather than in a draw.
The hosts are expected to be without midfielder Valentin Stocker, who recently picked up a groin problem.
Meanwhile, the Romanian outfit have an injury concern of their own over midfielder Mihai Pintilii.
Steaua have not won on any of their last four trips to Switzerland, while Basel have won two of their last three encounters against sides from the Transylvania region.
Possible starting lineups
Basel: Sommer; Voser, Ivanov, Xhaka, Ajeti; Delgado, Serey Die, F Frei, Salah, El Nenny; Streller
Steaua: Tatarusanu; Szukala, Parvulescu, Varela, Filip; Gardos, Chipciu, Tanase, Bourceanu, Kapetanos; Tatu
Sports Mole says: 2-1