Barcelona forward Lionel Messi is doubtful for Saturday night's Primera Division game at Villarreal due to an adductor injury.
Messi, 23, was missing due to the problem as Costa Rica held Argentina to a draw in their goalless friendly in San Jose on Tuesday.
He suffered the injury in training with his national team and coach Sergio Batista elected not to risk the FIFA Ballon d'Or winner - much to the annoyance of the supporters, who had hoped to see the superstar in action.
Speaking before kick-off at the new Estadio Nacional, Argentinian Football Association president Julio Grondona said: "We just had a chat with the president of the Costa Rican Football Federation and the doctor, and Messi has a minor injury.
"The doctor has reviewed it and sees that it is not as it should be. Obviously, caution must be taken in these cases and, thinking about everything, we must be sure that the player is able to play - and he is not.
"He has a muscle strain and we do not even know if he will get to play Saturday."
Barcelona confirmed on Tuesday that another forward, Bojan Krkic, is also a doubt for the trip to El Madrigal after straining his ankle while playing for Spain Under-21s on Monday.