Barcelona midfielder Xavi is nursing a knock and will undergo a fitness test on Tuesday to determine whether he is capable of lining up against AC Milan.
The 32-year-old missed training on Monday and faces a race against time to be ready for a crucial UEFA Champions League clash.
With a quarter-final showdown between the reigning champions from Spain and Italy evenly poised at 0-0 from the first leg in Milan, there is all to play for at Camp Nou.
Barca will be confident they can get the job done on home soil, but they will be desperate to have the creative talents of Xavi at their disposal.
He is, however, nursing a calf complaint and Pep Guardiola faces an anxious wait before discovering whether or not the World Cup winner will be available to him.
"It is two days that Xavi has had the problem," said the Barcelona coach.
"We therefore decided not to push him to hard. He will undergo further examinations on Tuesday morning and we will see then whether he can play or not.
"But he is nevertheless in the squad."