Last year's Champions League victor must overturn a 1-0 deficit to progress, but will be confident of success after going unbeaten at Stamford Bridge in Europe this term.
Fernando Torres should lead the line with Demba Ba cup-tied, while John Terry should return at the heart of Chelsea's defence.
John Obi Mikel and Eden Hazard made distinct impacts as second-half substitutes against Sir Alex Ferguson's charges, so are likely to start from the off on Thursday.
Meanwhile, Steaua coach Laurentiu Reghecampf may be tempted to stick with the same starting lineup that beat Chelsea in the first leg in Romania. However, Reghecampf may have the opportunity to tinker if Daniel Georgievski can recover in time from a fibula injury.
Elsewhere, forward Stefan Nikolic could also return from a knee problem, while Brazilian striker Adi Rocha is waiting in the wings to deputize.
|DID YOU KNOW?|
- Steaua's first-leg victory over Chelsea represented the first ever competitive meeting between the two sides.
- Frank Lampard has registered the most Chelsea appearances in UEFA competitions, having played over 100 times in Europe for the Blues.
- In four European home games this season, Chelsea is yet to taste defeat with two wins and two draws.
- The Blues' top scorer in European competition this term is Oscar. The Brazilian has scored six times in total, with his last goal coming against Sparta Prague in the last-32 first leg.
- As well as topping their Europa League group this season, Steaua Bucharest is 12 points clear at the top of their domestic league.
- Steaua has also won its last five games in all competitions.
- The Romanian side overturned a 2-0 first-leg deficit against Ajax in the last 32, eventually clinching the tie 4-2 on penalties.
- Striker Raul Rusescu (pictured right) scored the winner against Chelsea six days ago and has notched 18 league goals this season, also striking four times in the Europa League.