FC Barcelona crushed Real Betis' 5-2 reading in a Spanish league match on Saturday.
However, Ansu Fati made a spectacular save.
The 18-year-old Spaniard had to be replaced at half-time.
After the match, it became clear that the reason for the change was a knee injury.
Barcelona later confirmed on Saturday that a torn helix had been found in Fat’s left knee.
The Catalan Society did not state how long the young man would go on sick leave.
Barcelona said it would announce the injury to its gold lump in the coming days.
Fati have scored five goals in ten matches this season.
He had been selected to the Spanish A national team for next week’s international matches.
Recovery from a spiral injury can take from a couple of weeks to several months depending on the nature of the injury.
The Spanish media suspected that Fati would no longer play during this calendar year.
Lionel Messi, who was replaced by Fati, decided to play the match in the second half.
The Argentine star hit just over an hour from the penalty kick and twenty minutes later with a handsome top corner shot.
Ousmane Dembele, Antonie Griezmann and Pedri were the other goals for Barcelona.
Betissa’s Aissa Mandi was driven out just moments before Mess’s second goal.
The Catalans rose to seventh in the league table with their victory.
Barcelona is six points top team Real Sociedadia behind.