An injured player can damage the team and this can make a change in the tactics they are planning for this game.
The good news for Real Madrid is about the payler of Macsnther City, Joško Gvardiol the Croatian player of this team. In the game against Crystal Palace in which they won the game with a 4-2 result, Joško Gvardiol got injured.
Guardiola didn't say anything clearly about this player but the absence of this right-back player can definitely damage Manchester City.
Gvardiol is a talented central defender and he is an important piece in Manchester City defense system. If he can not play for them in two quarter final matches against Real Madrid, it's big loss for Manchester City in player resource and can affect their performances.
Sportsgambler.com does not have information about Gvardiol's injury but Manchester City have two other defensive players, Ake and Walker, in list of injured players. Manchester City will have to pray for good recoveries from Ake and Walker as they need these players in Champions League.
City is still using Lewis as Walker's replacement, and he did pretty well in the last matches. There's no need to worry about that since we have Lewis, who played as a wing back. City can change the scheme to see three CB. akan is also ready to play against real madrid since he has been also playing in EPL.
I think Pep has an alternative solution when some players are not ready to face Madrid. We have Akanji, Dias, and Stones when we play three backs. I'm not even worrying if Walker and Nathan ake will not be able to play.
I must admit if city will be even stronger when it plays with 4 backs.