As a consequence of their intense workload over the last few weeks, City have lost key players such as Aleksandar Kolarov, Vincent Kompany, Eliaquim Mangala and Wilfried Bony while Kevin De Bruyne went down with a serious looking knee injury in the Capital One Cup semi-final second leg triumph over Everton on Wednesday night.
Pellegrini has his options limited as a result and has hinted that he may not be able to put out his most ideal XI when his side takes on Villa on Saturday.
Pellegrini said: "We will see tomorrow and then start the best starting eleven against Aston Villa.
"It's difficult as we have to play nine games in February. It's important for us to keep a winning mentality in all competitions, but we'll see tomorrow what is the best starting eleven for that game.
"It is not easy as we have injuries to Kolarov, Kompany, Mangala, Bony and De Bruyne, but we will try and put an eleven on the pitch that will allow us to keep us in the FA Cup also."