Why is Pep Guardiola not managing Man City vs Sheffield United?

The Catalan coach has suffered from back pain for more than a decade, with the problem dating all the way back from when he was coaching Barcelona. The pain got particularly bad following City's win over Newcastle and the coach decided to fly to Barcelona to undergo surgery.

"Pep Guardiola has today undergone a routine operation on a back problem," said a statement from City on Tuesday. "The Manchester City boss has been suffering with severe back pain for some time lately, 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."

City have not confirmed exactly how long Guardiola will be out for as it depends on how quickly he recovers from the back surgery. However, the club hope he will return to work in mid-September.

"He is expected to return after the forthcoming international break," added City's statement. "Everyone at Manchester City wishes Pep a speedy recovery, and look forward to seeing him back in Manchester soon."

Guardiola is likely to miss two matches. He will be absent from City's visit to Sheffield United in the Premier League on Sunday as well as their home match against Fulham on September 2. Assuming his recovery goes well, he will be back in the dugout when City visit Wolves on September 16.

Guardiola's assistant coach Juanma Lillo is taking charge of the team in his absence. Lillo has been taking training since Tuesday and did Friday's press conference. He will be on the sidelines in the away match at Sheffield United and the home game against Fulham.

Lillo, who is from Tolosa in the Basque Country region of Spain, has been a coach for more than 40 years. He had no playing career but has worked as a head coach for 17 different clubs and as an assistant with Chile, Sevilla and Manchester City, in two separate stints.

Lillo has never won a trophy as a head coach but is widely respected within the game and Guardiola sees him as a mentor. He first became a coach at the age of just 17 with local club Amaroz Ke.

In 1995 he became the youngest coach in the history of La Liga, guiding Salamanca up to the top flight when he was just 29, overseeing their rise up the leagues from the third-tier Segunda Division B.

He has also coached Real Oviedo, Almeria, Real Zaragoza and Real Sociedad amongst a host of other lower league clubs.

Lillo first met Guardiola in the 995-96 season, when his Real Oviedo side were beaten 4-2 by Barcelona, who were then captained by the current Manchester. Lillo recalled:

"We lost 4-2, but we played really well. Suddenly, there was a knock on the dressing room door and Pep was there; he hadn't changed yet. He had come to ask me if I minded chatting for a minute – as if I was going to be annoyed about talking to the best centre-midfielder in the history of football.

"He told me he loved how I put my team together and wanted to stay in touch. What started as a professional thing soon turned into much more.”

Guardiola admired Lillo so much that he signed for Mexican side Dorados Sinaloa just so he could learn under the Basque coach. The pair stayed in touch and Guardiola appointed Lillo as his assistant coach at City in 2020.

City won back-to-back Premier League titles with Guardiola and Lillo although the assistant left in 2022 to become head coach of Al Sadd in Qatar. However, he returned to Guardiola's coaching set up this summer after Enzo Maresca became head coach of Leicester City and Rodolfo Borrell left to become sporting director at MLS side Austin FC.