Manchester City midfielder Rodri has ligament damage in his right knee, the club said Wednesday without giving a time frame for his potential absence.
The Spain international, who is among the favourites to win this year's Ballon d'Or award for the best player in the world, limped off after 20 minutes of the 2-2 draw against Arsenal in the Premier League on Sunday.
The 28-year-old Rodri travelled to Spain on Monday to seek specialist consultation on the problem and City has confirmed he suffered a ligament injury.
Assessment remains ongoing to ascertain the full extent of the injury and expected prognosis, the English champions said.
City manager Pep Guardiola said Tuesday he expects to be without Rodri for "a long time" but revealed there were "some opinions that it will be less than we expect.
We're waiting for the last phone calls from the doctors to know exactly what definitely he has and the type of surgery he has to get, Guardiola said after City's 2-1 win over Watford in the English League Cup.
Rodri's absence is a major blow to City's ambitions of winning a record-extending fifth straight Premier League title this season as he is arguably the team's most important player because of how he protects the defense and conducts its passing game.
His importance to Guardiola's team was underlined last season when City lost four of nine games without the inspirational midfielder in all competitions. By comparison, City lost just one of 50 games with him in the team.
Guardiola said Tuesday that Rodri is the best midfielder in the world and described him as irreplaceable.
Rodri fell to the ground in pain after jostling with Arsenal's Thomas Partey in the box at a corner and immediately called for help. He was starting a game for the second time this season after being granted an extended break by City following the European Championship, which Rodri won with Spain in July.
He was also voted player of the tournament at Euro 2024.
Just last week, Rodri said top players could soon go on strike because of the number of games they are being asked to play as new competitions are introduced to an already-packed soccer calendar and matches are added to existing tournaments.
The Champions League has been expanded this season with two more games for each club in a new-look league stage in the first round. Next year's expanded Club World Cup will be a 32-team event for the first time and is slated to take place during the offseason for many major leagues, in June-July.
The new Club World Cup format has prompted a legal challenge from players' unions.
On Tuesday, Manchester United manager Erik ten Hag said the risk of more injuries to top players was almost unavoidable because of the increased demands on players.
