Lionel Messi will sit out Barcelona's Champions League tie against Celtic on Tuesday because of a thigh injury.
The 26-year-old limped off in Barcelona's 2-0 win over Almeria last night, and is expected to be out of action for up to three weeks.
"Leo Messi has a small injury to the biceps femoris [thigh] in his right leg," a Barcelona statement read.
"This was confirmed by medical tests undertaken by the player on Sunday morning at Medical Services Sport City.
"The Argentinian will be out for approximately two to three weeks, which will certainly force him to miss Barcelona's two games this week - on Tuesday against Celtic and next Saturday at the Camp Nou against Valladolid."
The loss of Messi comes as a further blow for Barcelona, who have been hit by a series of injuries in defence.
The Catalan club are currently without Javier Mascherano and Jordi Alba, while captain Carles Puyol is still not fully fit despite returning to training.
Despite their injury woes, Barcelona cruised to their seventh-straight La Liga win last night, thanks to goals from Messi and Adriano.
The victory means Barcelona have now had their best ever start to a La Liga season, and they are already five points clear of rivals Real Madrid, who stumbled to a 1-0 defeat against second-placed Atletico Madrid last night.
Celtic sprung one of the greatest Champions League surprises ever last season when they secured a 2-1 win over Barcelona at Celtic Park.