Pep Guardiola has confirmed that Rodri will miss the rest of the season after rupturing his anterior cruciate ligament (ACL).
The Spaniard limped off in the first half of City's 2-2 draw with Arsenal after turning awkwardly in a tussle with Thomas Partey on a corner.
Reports soon claimed Rodri could be out for the rest of the season with the serious-looking injury, and he later visited a specialist in Barcelona.
Guardiola had said on Tuesday that Rodri was facing a long spell on the sidelines, describing him as "irreplaceable", with the club confirming it was a ligament injury the following day.
Now, speaking ahead of their Premier League trip to Newcastle United on Saturday, the manager explained the extent of the midfielder's injury.
"[Rodri had] surgery this morning [on his] ACL and next season he will be here. This season is over," Guardiola told reporters.
"Unfortunately, we got the worst [news] but these things happen. We will be there to support him in his recovery step-by-step.
"What he gives us, we don't have a similar player. But the others can all together replace what Rodri has given since his arrival to us.
"We will have to do it as a team and find a way to play a lot of matches without an important player for us.
"If we don't win, then it is because of Rodri. We are stronger with him and stronger with [Nathan] Ake and [Oscar] Bobb and Kevin [De Bruyne] but that is what it is. We don't want it, but it is football.
"As a club, we have magnificent players, and we will find a solution."
Each of City's last four Premier League defeats have all come when Rodri has not featured in the side. Indeed, the 28-year-old is unbeaten in his last 52 Premier League appearances (W42 D10), a run stretching back to February 2023.
City only lost one of the 50 matches in which Rodri appeared across all competitions last season – the FA Cup final against Manchester United – and their win percentage dropped from 76% to 55.6% in the nine games they played without him.
Asked if City would bring in a replacement for the midfielder in the January transfer window, Guardiola added: "We will talk, we will see what is going on. We have time to see."