Barcelona midfielder Pedri injured his hamstring in the 2-2 home draw with Manchester United in the Europa League, his team said on Friday, with domestic media reporting that the Spain international will be out for up to four weeks.
Pedri came off in the first half of the draw on Thursday. He was replaced by Sergi Roberto.
Barcelona's statement did not say how long Pedri will be out, but Spanish newspaper Diario AS said he could be sidelined for four weeks, ruling him out of the second leg at United as well as a Copa del Rey game against rivals Real Madrid.
"FC Barcelona's Pedri has injured the rectus femoris muscle in his right thigh (hamstring)," Barcelona said in a statement.
"The news comes as real blow to Barca, for Pedri has been in tremendous form of late and has played a key role in the long unbeaten run."
Barcelona top LaLiga on 56 points from 21 games. They next face 16th-placed Cadiz on Sunday.