MADRID, Sept 25 (Reuters) - Barcelona's injury crisis deepened on Wednesday after tests confirmed first-choice centre back Javier Mascherano will be out of action for upto 15 days after damaging a thigh muscle in Tuesday's 4-1 La Liga win at home to Real Sociedad.
With left back Jordi Alba sidelined and captain Carles Puyol yet to return from a knee surgery, Mascherano's injury is a fresh blow to coach Gerardo Martino ahead of Tuesday's Champions League Group H match at Celtic.
The Argentina international sustained the injury in a collision with team mate Sergio Busquets in the second minute at the Nou Camp and eventually had to be replaced by Marc Bartra just after the half hour.
"A strain in the right thigh muscle was confirmed which will put him out of action for 10-15 days," Barca said on their website (www.fcbarcelona.es) on Wednesday.
Mascherano's absence may give 22-year-old youth academy product Bartra a chance to shine, although Puyol is close to a return to competitive action.
As well as the Celtic match, Mascherano is likely to miss Barca's La Liga games against Almeria and Real Valladolid.
He may recover in time to feature for his country in their World Cup qualifiers against Peru on Oct. 11 and Uruguay on Oct. 15, although Argentina are already through to next year's finals in Brazil. (Reporting by Iain Rogers, editing by Amlan Chakraborty)