Hansi Flick has been dealt a fresh blow ahead of next Sunday's Clasico against Real Madrid at the Camp Nou, in the tenth round of the Spanish league.
Dani Olmo limped off during Barcelona's Champions League defeat to Paris Saint-Germain on Tuesday, a 4-2 loss for the Catalans in Paris.
Spanish newspaper "AS" reported that the Spain international left the Parc des Princes pitch frustrated, clutching his thigh, before being replaced by Fermin Lopez in the 27th minute.
Early reports point to a tear in Olmo's left thigh muscle. It's a serious injury that will rule him out of the Clasico and other matches to follow.
Nothing will be confirmed, though, until Wednesday, when Olmo undergoes an MRI scan in Barcelona.
AS added: "If a tear is confirmed, the recovery period could range between four and five weeks."
Flick can ill afford it. Olmo's setback lands just after Jules Kounde and Eric Garcia picked up injuries in the recent La Liga clash with Real Betis.