This brings to four the number of Premier League games to be postponed in the past week because of Coronavirus.
Tottenham, who have recently been hit with an outbreak themselves, saw their game against Brighton and Hove Albion over the weekend postponed while Brentford against Manchester United and Burnley versus Watford have all been postponed this week.
Tottenham now have three games to catch up, having already had one game against Burnley called off because of poor weather.
A club statement from the King Power Stadium outfit read: "Leicester City can confirm that the Premier League Board has decided to postpone Thursday night’s fixture against Tottenham Hotspur.
"The decision was taken with guidance from medical advisors after the club resubmitted its application for postponement after confirmation this morning (Thursday) of further positive tests for COVID-19 within the first team squad. As a result, the club has an insufficient number of First Team players available to fulfil the match.
"Given the increase in positive tests among first team personnel, first team operations at Seagrave will now be closed for 48 hours, serving as a circuit breaker to help reduce the risk of further infection. First team players and staff will undergo a subsequent round of testing on Saturday.
"The club regrets the inconvenience caused to Tottenham Hotspur and both sets of supporters by Thursday night’s postponement."
