Eric Abidal has been admitted to hospital for examination on his transplanted liver.
The Barcelona defender, who had a tumour removed in 2011, received part of his cousin's liver in a surgical procedure in April last year.
Abidal was cleared to resume playing in December but has not appeared for Barca since then.
A statement from the club read: "Eric Abidal will spend between three to four days at Barcelona's Hospital Clinic for examinations of the development of the transplant that he underwent last April.
"By express wish of the player, the club is asking for the utmost respect for his privacy and confidentiality."