After last night's semifinal win against Newcastle, Guardiola insisted January signing Marc Guehi should be allowed to play in the final in March.
As it stands, Guehi is Cup-tied after joining City from Crystal Palace last month.
But Guardiola insists: "Hopefully we can arrive with players fit and hopefully we can convince the Carabao Cup that Marc can play in the final because it's difficult to understand. The club made a big investment to take one player.
"He belongs to us and I don't understand why he cannot play the final.
"Hopefully we make a letter and hopefully the Carabao Cup or whatever can understand that when you buy a player for a lot of money and he is not able to play for a rule, I don't understand why.
"Hopefully they can change it."