The 22-year-old has emerged as a doubt for the trip to the King Power Stadium after he came off at half time in the goalless draw with former club Borussia Dortmund on Wednesday due to a combination of fatigue, illness and a minor foot injury.
Guardiola has since provided a positive update on the Norwegian’s condition, but insists that he is still unsure whether the striker will be fit to feature on Saturday.
Speaking at a press conference on Friday afternoon, Guardiola said: “[Haaland] feels better but we will train this afternoon and we will assess in a few hours.
“We will see how he feels in his foot and then we will decide. I will know in two hours if he’s able to play or not.
“After the [Dortmund] game everyone trained well. I have to wait for the people coming back to know exactly how they feel.”
City have relied heavily on their new number nine in front of goal so far this season, with the 6ft 5in goal machine already netting 22 times in just 16 appearances across all competitions, including 17 strikes in 11 Premier League games.
However, Haaland has failed to find the net in two of his last three appearances and he may not be able to add to his tally on Sunday if he is deemed unfit to feature against the Foxes.
Guardiola has suggested that Julian Alvarez is his “first option” to play in attack if Haaland is unavailable for selection and the Citizens boss is confident the Argentine can pose a similar threat in front of goal.
“Normally if Erling [Haaland] is not ready then Julian [Alvarez] is the first option,” Guardiola added. “He can play false nine but I think this is not going to happen. When Erling is not ready then Julian is the first option.
“[If he plays] 90 minutes every game, he will score goals, maybe not like Erling, but he will score goals.”
Guardiola has also provided an update on English duo Kyle Walker and Kalvin Phillips, who have been recovering from respective groin and shoulder surgeries.
Sunday’s fixture will come too soon for both players, but Guardiola remains optimistic, particularly about Phillips, that they can return in time to represent England at the World Cup next month.
“They are getting better, Kalvin especially, but they are both out,” said Guardiola. “[Phillips] feels really well, his mobility in his shoulder is perfect.
“He has to avoid contact with his teammates at the moment. If he is fit and I believe he can play then maybe he can make some minutes [before the World Cup].
“They are positive, optimistic, they are in touch with Gareth [Southgate]. I don’t know, hopefully they can be ready to be selected.”
Guardiola has also confirmed that goalkeeper Ederson will return between the sticks after handing Stefan Ortega his Man City debut against Dortmund.
The Citizens will momentarily climb to the top of the Premier League table with a victory over Leicester, before current leaders Arsenal play host to Nottingham Forest on Sunday.