Eric Abidal has issued a statement after it was alleged that former Barcelona president Sandro Rosell had illegally purchased a liver on the black market for the Frenchman in 2012.
Abidal had a transplant six years ago after a tumour was discovered in his liver. It was claimed at the time that the liver donor was Abidal's cousin Gerard.
But reports from Spain claim that Rosell, the Barca president at the time, purchased the organ illegally, with wire-tapped phone recordings used to support that allegation.
Barcelona have strongly denied the accusations and now Abidal has also issued a statement condemning these reports.
"I feel obliged to communicate my annoyance and sadness in relation to today's news about me alleged illegal liver transplant," wrote Abidal on his Twitter account.
"Out of respect for my family, the medical team, and everyone who has undergone a similar situation, I would like to sincerely apologise if at any point there have been doubts about the unsoundness of the news published today.
"My cousin Gerard donated his liver to save my life and for this I am truly grateful to him. Existing procedures and protocols were followed at all times and all the medical documentation that proves so is available."
Barcelona's statement reads: "FC Barcelona denies any irregular fact in liver transplantation as it has done the interested party and the Hospital Clinic."
After the transplant, Abidal played five more times for Barcelona. He went on to play for Monaco and Olympiacos before retiring in 2015.