It's not a fibrillar rupture, nor is it a hard knock received at training, nor did someone hurt him. The injury that Ansu Fati has had for more than a week is because of a growth spurt.
According to the Catalan newspaper, the young winger is fully growing, which causes pain in the bones, mainly in the right knee. It's annoying, but not worrying and must be kept under control.
Furthermore, the news is that Ansu Fati, who is currently 1.78m, could grow to 1.80m, and be able to get more muscle.
It is still not clear when he will be available for Valverde's men, although it is estimated that it could be in time for the weekend's clash v Sevilla.