Sevilla have announced that defender Sergio Sanchez has a heart condition which will require 'rigorous tests'.
Sanchez has now travelled to Barcelona to be with his family and will not be considered for selection until the problem has been thoroughly examined.
An official club statement read: "Sanchez is suffering from a cardiac pathology which demands the suspension of all physical activity for the time being."
Sanchez joined Sevilla from Espanyol last July, and has been competing with Abdoulay Konko for the right-back slot.
Spanish players called for improvements in screening procedures for heart problems following the death of Espanyol defender Dani Jarque in August, two years after Sevilla midfielder Antonio Puerta collapsed during a game and later died after a prolonged cardiac arrest.