Manchester City midfielder Rodri has been pictured arriving in Spain ahead of tests on a right knee injury sustained against Arsenal in the English Premier League at the weekend.
Rodri underwent further tests in Barcelona on Tuesday. A source told ESPN he will undergo surgery, but there is a small possibility that the cruciate ligament is not as affected as first feared.
If the cruciate ligament is affected he will be sidelined for around eight months. If not he will be out of action for around five months.
Speaking ahead of the team's Carabao Cup match against Watford on Tuesday, Man City manager Pep Guardiola confirmed only that Rodri will be out of action "for a while."
"We are still waiting for the decision of the doctors, exactly what he has," he added to Sky Sports. "When we know it, the club or myself, or the spokesman of the club will announce it."
Sections of the Spanish media published footage on social media of Rodri arriving in Barcelona on Monday.
If Rodri is missing for a long period of time, it damages City's chances of winning the Premier League for a record-extending fifth straight season. City lead the league by a point after five games.
Rodri, among the favorites to win the Ballon d'Or for 2024, is arguably City's most important player because of how he protects the defense and conducts the team's passing game.
He limped off in the 20th minute of the 2-2 draw with Arsenal at Etihad Stadium on Sunday after hurting his right knee when jostling with Arsenal's Thomas Partey in the box at a corner.
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.
Information from The Associated Press contributed to this report.