The Blues, who have already qualified from Group E, take on the Romanian giants knowing that a win will see them finish top of the standings.
However, Mourinho is keen to rest a number of players ahead of Saturday Premier's League encounter against Crystal Palace at Stamford Bridge.
"I don't want to call it rotation because when you say rotate it comes with an idea that the team is weak. That's not the case," he told reporters. "I won't play the same team as the last match because some players need a little rest."
Chelsea earned a comfortable 4-0 win over Steaua when the teams met in the reverse fixture back in October.