The Citizens hosted Borussia Dortmund in the Champions League on Wednesday and will have just two days' rest for their encounter against the Black Cats at the Etihad Stadium.
"We need to recover very well because we play early on Saturday and I don't understand this," the Italian is quoted as saying by The Guardian. "It's incredible that we play Wednesday night and then Saturday at 12.45pm.
"We have two days and 12 hours to recover very well. We didn't play a good game but we lost a lot of energy in this game and we need to recover.
"Everywhere else the teams that play in the Champions League play three or four days before the game and have three days minimum afterwards. Here it is strange."
City are currently fourth in the Premier League table with 12 points from six matches, four points behind leaders Chelsea.