Spain and France hoping Abidal can attend
Valdes, a team-mate of Abidal's at Barcelona, said the operation to remove a tumour from his liver and his subsequent transplant had been a "very tough time" and he hoped the 32-year-old would be able to make a return to action before long.
"He is continuing with his recuperation but I hope he can come to the match," Valdes told a news conference at Spain's training base in Gniewino, northern Poland.
"With everything that happened it has been a very tough time and it would be a great joy for both teams to see him in the stands," he added.
"I just want to send him and his family and friends words of support and the most important thing is that he gets well so that he can return to playing with us once more as soon as possible.
"He brings very positive things to a team as a person and a footballer and it's a shame he is not able to play this match."
Abidal was invited to France's Group D game against Sweden in Kiev on Tuesday, which they lost 2-0, but he did not attend the match.
The French football federation said it did not yet know whether he would be at the game against Spain, who as well as Valdes have Barca players Xavi, Andres Iniesta, Cesc Fabregas, Sergio Busquets, Gerard Pique and Pedro in their squad.
Abidal has played 61 times for France and was part of the team that finished runners-up at the 2006 World Cup. He also played in Euro 2008 and the 2010 World Cup in South Africa.