Pep Guardiola is set to miss the next two Manchester City games after a "routine operation" to correct a persistent back injury.
City said their treble-winning manager had been suffering from "severe back pain for some time" and he flew out for surgery in Barcelona where he will remain to begin his recovery.
The Spaniard, who will remain in Barcelona while he recovers from the operation, is expected to miss City's matches at Sheffield United this Sunday and Fulham on September 2 at the Etihad Stadium, with assistant manager Juanma Lillo taking charge in his absence.
The club season then takes a two-week break for international matches before City return to Premier League action against West Ham United on September 16 – when Guardiola is expected to return – with the Champions League group stage kicking off the following week.
"Pep Guardiola has today undergone a routine operation on a back problem," said the club in a statement.
"The Manchester City boss has been suffering with severe back pain for some time, and flew out to Barcelona for emergency surgery performed by Dr Mireia Illueca. The surgery was a success, and Pep will now recover and rehabilitate in Barcelona.
"In his absence, assistant manager Juanma Lillo will oversee coaching of the first team on the training field and will assume duties on the touchline until Pep's return.
"He is expected to return after the forthcoming international break. Everyone at Manchester City wishes Pep a speedy recovery, and look forward to seeing him back in Manchester soon."
Lillo, 57, is in his second stint as Guardiola's assistant at City, having held the position from 2020-22 after joining from Qingdao Huanghai in China following Mikel Arteta's exit to become manager of Arsenal.
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He left in June 2022 to take up a position as coach at Al Sadd in Qatar and had previously been a mentor to Guardiola as a player during their time together at Mexican club Dorados de Sinaloa in 2006.
But Lillo returned to his old role at the Etihad this summer, much to the delight of Guardiola. “Juanma sees things no one else in the game sees," he told the club's website earlier this month.
"He understands football on an incredible level, so he is the perfect person for me to work alongside. I have always been inspired by him – his knowledge of football, his intelligence and his humanity mark him out as a very special person in my life – and we have a shared ideology.
“He is a friend, a colleague and an inspiration. I am so, so happy he is back here at Manchester City. His preparation for matches is absolutely amazing. I know he will raise standards because he works so hard every single day."
City have started the new season with three wins out of three games after beating Burnley 3-0 and Newcastle United 1-0 in the Premier League, while also defeating Sevilla via a penalty shoot-out to lift the Uefa Super Cup.