Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
The 32-year-old was set to depart the Nou Camp on a free transfer this summer and join Monaco, but a serious injury has seen the big-spending French outfit withdraw their contract offer.
Valdes is still tied to Barca until the end of June and is receiving treatment after knee ligament surgery at the club's medical facility.
Marc-Andre ter Stegen has already signed for the Catalan giants from Borussia Monchengladbach and reports suggest that a deal for another experienced keeper is close.
However, should Valdes decide that he does not want to leave and requests talks about a new contract, Barcelona are not opposed to the idea.
"Like [Josep Maria] Bartomeu [the president] has said, the doors of Barcelona will always be open to Victor," club spokesman Manel Arroyo said.
Barca require a second goalkeeper after Valdes' number two, Jose Manuel Pinto, also left at the end of last season.
Rumours in Spain continue to suggest that the club are set to make an official move to sign Real Sociedad's Claudio Bravo, but a U-turn by Valdes could change their mind.