Barcelona will be without their captain Carles Puyol for their Champions League double header against Celtic.
The influential defender is out for at least eight weeks after dislocating his left elbow in the 2-0 victory over Benfica on Tuesday night.
After flying back to the Catalan capital, he spent the night in hospital where scans confirmed the extent of the damage done.
A spokesman for Barcalona said: "The club captain will undergo conservative treatment and is expected to be out for about eight weeks."
Puyol took to Twitter to inform fans of how he was doing in hospital and thank them for their support.
He wrote: "We are back in Barcelona. I want to thank everyone who looked after me in Portugal.
“I'll soon be back to my best again! Thank you for all your messages - a big hug to all of you."
The news was a blow to head coach Tito Vilanova, who will also be without Gerard Pique for the weekend El Clasico clash with Real Madrid.
Vilanova said; "I've always said it, we've always had problems with our central defenders, but we'll move forward.
"It's not just that we've lost Puyol for the Clasico on Sunday, but we've lost him for other matches as well.
"The injuries mean we will have to play players in positions that aren't their own, but we'll use our youth players to cover the absences, hat's why we have them."
Celtic play at the Camp Nou on Tuesday, October 23, before welcoming the four-time European champions to Celtic Park on Wednesday, November 7.
