Barcelona could be without Xavi Hernandez when they take on Paris Saint-Germain in the Champions League next week after the playmaker returned from international duty with more hamstring trouble.
Xavi was released for Spain's recent World Cup qualifiers despite Barcelona's medical staff voicing concerns that he could aggravate the injury, which has restricted his appearances in recent months.
The injury was assessed at Barca's Ciutat Esportiva on Thursday, and a statement from the club's medical staff said Xavi was a doubt for the game at the Parc des Princes.
"Club medical services have announced that Xavi Hernandez is suffering from a strained hamstring in his right leg," the statement said.
"On Thursday, he received treatment from the club physios... his availability for the next match will depend on his recovery.
"Xavi had a similar injury in the same leg in February and missed a number of league matches plus an international friendly in Doha as a result."
The problem has been managed by Barcelona after the midfielder was substituted early at Valencia in February.
Since then, he has completed only the two Champions League last-16 ties against AC Milan, playing parts of some games and sitting others out completely.
He has spoken during this time of his willingness to take injections to get through important matches, but is not expected to travel with the squad for the La Liga match at struggling Celta Vigo on Saturday.
Coach Tito Vilanova and assistant Jordi Roura are likely to give squad players such as Thiago Alcantara, Martin Montoya and Alexander Song a run-out, allowing others to rest before the match in Paris.
The injured Carles Puyol, Adriano Correia, Jordi Alba and Pedro Rodriguez are ruled out of the Celta game, as is the suspended Victor Valdes.