"The City forward was in Holland on his day off and has sustained injuries".
Mendy seemed in strong spirit despite the injury and tweeted he was joining Loan FC.
Guardiola suggested on Monday that Mendy still had a chance of featuring in the midweek Champions League game against Shakhtar Donetsk, but the defender was actually pictured on crutches at the game.
Earlier on Thursday night, Aguero posted a picture of himself on Instagram with the Colombian singer/songwriter Maluma. "I am not the police", the City manager said. "So now I don't think it's time to think about that".
"It was an accident".
City didn't give a likely timeframe for Mendy's absence.
"I don't know, we will wait until Thursday, but I am pretty sure it will be longer than we would like, unfortunately". He was scheduled to undergo surgery yesterday in Barcelona, after tests at the clinic of noted orthopaedic surgeon Ramon Cugat showed that the full-back ruptured the anterior cruciate ligament in his right knee.
Losing the 23-year-old for the majority of the season will be a big blow to City as he is not only an excellent player, he's also their only natural left-back. Like Mendy, both were summer signings.
City may now look to bring in a replacement for Mendy in January, who was signed from Monaco in the summer for £52million, with Pep Guardiola cursing his lack of present options.
City released left back Gael Clichy in the summer while Aleksandar Kolarov asked to leave to join Roma.