Barcelona believe that young midfielder Pedri may have suffered a significant hamstring injury which could keep him out for the remainder of the current season.
The 19-year-old started Thursday's 3-2 defeat to Eintracht Frankfurt but picked up the injury in the first half and complained of pain to the club doctor at half-time, leading to his withdrawal from the game.
While in-depth tests have not yet been conducted, the Barcelona medical staff are said to be worried by Pedri's injury and believe his season may be over.
Mundo Deportivo and AS both report that the initial diagnosis is that Pedri may have torn his hamstring, which could see him sidelined for the next two months.
"Pedri worries me, let's see what he has," manager Xavi said after the game. "It's very bad news."
Concerningly, Pedri's latest issue is in the same area as the injury which kept him sidelined for a number of months earlier this season.
The teenager went down with a hamstring problem in September and hit a number of setbacks before eventually returning in January, after which he quickly established himself as a key player under Xavi.
The boss recently had to deny suggestions that his side were dependent on Pedri, whose return from injury coincided with Barcelona's return to form.