Ferguson is faced with several injury concerns, particularly in defence, with Rio Ferdinand left at home in a bid to be fit for their league clash with Chelsea on Sunday, whilst Nemanja Vidic and Rafael da Silva are also sidelined for Wednesday's match.
Speaking to reporters ahead of the match at the Estadio da Luz, Ferguson said: “The season starts when the Champions League comes around because then you are into games all the time.
"We have the game tomorrow, Chelsea on Sunday, Leeds United next Tuesday, Stoke away the following Saturday, so obviously the squad will be used.
"Rio has stayed behind as a precaution and Vidic has not started training yet, so that will be at least two weeks.
"I have not decided about tomorrow yet but it wouldn't worry me to play the team that has been doing well."