The Swans lost the third-round tie 2-1 to City at the Liberty Stadium on Wednesday night but not before some solid displays from midfielder Britton and promising youngster Jay Fulton.
"I saw Leon play a very, very important game," Guidolin said after the game.
"I don't know if he can start again on Saturday because there's not a lot of time to rest. We will have to see.
"Jay Fulton also played well. I am happy for the whole team."
Swansea next meet City at home again in the Premier League on Saturday.