Antonio Conte is set to undergo surgery and take a leave of absence from Tottenham.
The Spurs manager has been diagnosed with an inflamed gallbladder, which requires removal, after becoming unwell with “severe abdominal pain”.
The Italian could now miss a crucial period for the club, who sit fifth in the Premier League.
“Antonio Conte recently became unwell with severe abdominal pain,” said a Tottenham statement.
“Following a diagnosis of cholecystitis, he will be undergoing surgery to remove his gallbladder today and will return following a period of recuperation.
“Everyone at the club wishes him well.”
Conte was in charge for Tottenham’s 3-0 FA Cup win against Preston on Saturday but will likely be absent as Manchester City visit the Tottenham Hotspur Stadium on Sunday.
Gallbladder removal surgery, also known as a cholecystectomy, is usually carried out after the formation of gallstones in the bile-storing organ.
The procedure is most often performed as a keyhole surgery, which usually allows patients to leave hospital on the same day or morning after undergoing general anaesthetic, according to the NHS.
The health body adds that people are generally “able to return to most normal activities within two weeks”.
Spurs, who completed the signing of Pedro Porro from Sporting Lisbon on deadline day, have a six-day gap after meeting the champions before travelling to face Leicester, but then fave a short turnaround before the first leg of their Champions League last-16 tie against AC Milan on Tuesday 14 February.