World Cup winner Antoine Griezmann is expected to miss Barcelona's final two league matches after sustaining a quadriceps injury.
Griezmann was substituted after suffering the problem in the 1-0 win at Real Valladolid on Saturday which pulled Barca to within one point of La Liga leaders Real Madrid.
However, Madrid have a game in hand and are firm favourites to win the title, with Barcelona needing to win their remaining two matches and hope Madrid fail to win at least two of their last three, suffering at least one defeat.
"Tests this morning have shown that first-team player Antoine Griezmann has a muscle injury in the quadriceps of his right leg," Barcelona said in a statement.
"He is therefore not available for selection at the present time and the evolution of the injury will condition his availability."
Barcelona host Osasuna on Thursday and Alaves on Saturday, with Griezmann, who was man of the match when France won the FIFA World Cup in 2018, unlikely to feature in either.
Australian Associated Press