Barcelona coach Pep Guardiola on Friday said he was confident that the club's French defender Eric Abidal will return to the pitch after a scheduled liver transplant, calling the player "irreplaceable".
But the internationally-renowned head of Spain's organ transplant service expressed doubts that the 32-year-old would be able to play top-flight football, given the risks of injury.
Guardiola, though, was thinking positively, telling a post-training session news conference: "He knows he has all our support because he is much-loved.
"What really matters right now is to find a solution to this illness so he can get on with his life.
"He has to fight and he will do it. I am sure he will return. Not having him available to play is not what is important. He is irreplaceable for us. We don't have a substitute. He gives us an infinite range of possibilities."
Barcelona announced on Thursday that Abidal would have a liver translant "in the coming weeks", nearly a year after the player had a tumor removed from the same organ.
The club did not give any indication of how long he would be out of action but the operation puts him in doubt for the French team in the June 8-July 1 Euro 2012 finals in Poland and Ukraine.
Organ transplant specialist Rafael Matesanz had earlier told the Marca newspaper that it would be "very difficult" for Abidal to play again.
"It's clear that everything will go well and that he could play sport at a high level but football is a contact sport and one of the things that you have to avoid after a transplant is trauma and blows in that area," he was quoted as saying.
Matesanz said Abidal was "a strong person, an elite sportsman and he will have a normal life. And it's clear that he will be able to play sport".
But he added: "He has to take a series of precautions for the rest of his life, including not getting hit in that area. He will have medical treatment for life and will have to have regular check-ups."
France national coach Laurent Blanc said he was more concerned about Abidal's health and the effect on his family rather than discussing when -- or if -- he would play again, including in the Euros.
"It's not the thing that's uppermost in my mind at the moment," he said.
"At times like these, there's not a great deal you can say. It's sad news for Eric... it goes beyond football," Blanc told the French Football Federation's web site.
Abidal made a rapid recovery after undergoing surgery to remove a tumor from his liver in March 2011 and drew loud cheers as he made a symbolic return May 3 in the final minutes of Barca's return 1-1 Champions League semi-final tie with Real Madrid.
"He has behaved impeccably," said Guardiola. "He has taught us so many things, but I imagine it's not easy for him on the inside. If he's loved so much it's because he has won that love.
"The Camp Nou's ovation in the semi finals of the Champions League was one of the most amazing things I've ever seen. He's a very good person and very much loved by the squad.
"If people love him so much it's because he has earned it. I'm sure that that will give him a lot of strength to get through this."
Abidal's contract had been due to expire at the end of the current season but in January he agreed a new one-year deal with Barcelona which ties him to the club until 2013 with options to extend it by two more years.
The defender has been a regular this season for the Catalan side, starting in 20 first division matches.
But he has not played since picking up a hip injury playing for France in their friendly win over Germany at the start of March.