Lionel Messi has been ruled out of Barcelona's Champions League trip to Celtic (watch live on ITV) after suffering a thigh injury in Saturday night's 2-0 win over Almeria.
Messi scored his 11th goal of the campaign before being forced off after 28 minutes and scans on Sunday confirmed he would miss "two to three weeks".
The forward is therefore set to miss the trip to Glasgow - where Barca were beaten last season - and adds to the Catalan club's injury problems ahead of the game.
"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."
Barcelona are already set to be without a large chunk of their defence for the midweek trip to Scotland due to injury.
Javier Mascherano, who has been in good form this season, was ruled out in midweek with a hamstring problem to join Jordi Alba, who is suffering the same injury.
Veteran centre-back Carles Puyol is still recovering from his long-term injury problems.
The news will be welcomed by Neil Lennon's Celtic, who sprang one of the surprises of last season's Champions League group stage when Tony Watt's late winner inflicted a rare defeat on a Barca side that did include Messi that night.
Messi's injury overshadowed Barcelona's 2-0 win over Almeria which ensured a club-record seventh straight win to begin the Primera Division campaign.
Barca have never before strung together that many wins at the start of a season since La Liga began in 1928, although they remain level with Atletico Madrid at the top of the standings after Diego Simeone's side beat city rivals Real 1-0.
Barcelona expect to have the majority of their injured contingent back after the international break.