Real Madrid and Lyon have been told they will not be allowed to wear t-shirts wishing Barcelona defender Eric Abidal well before their Champions League tie at the Bernabeu on Wednesday.
Abidal was found to have a tumour on his liver earlier in the week and he will have surgery to remove this, with the procedure now brought forward to Thursday.
The two clubs had appealed to UEFA to relax a rule which forbids any emotional slogans being worn on clothes at Champions League games. But European football's governing body refused to make an exception.
Barcelona confirmed on their official website that the former Lyon, Lille and AS Monaco left-back, 31, will have surgery earlier than initially expected. At present it is not known how long the player will be out for or if he stands any chance of playing again this term.
President Sandro Rosell said: "Barca is 100% behind Eric Abidal. Health is more important than anything else in life. Abi, Barca loves you."
Barcelona midfielder Xavi also voiced his support after speaking to Abidal prior to training on Wednesday.
"It's the worst moment I've experienced in a dressing room," Xavi said. "It's a very sad day for all of us. These are difficult times for him and his family. He's always been an example for the dressing room, not only football-wise, but of attitude. Mentally he is one the strongest people I've met and this is going to help him a lot.
"When he came into training we gave him all the encouragement in the world. His mood surprised us, he's almost given us more encouragement than we have him, that shows his mental strength.
"He is an example of positivity. He told us to continue as always and that on Saturday we beat Getafe. We will try to dedicate a victory to him and his family.''