The Chelsea manager believes his Real Madrid successor Carlo Ancelotti should pick the Spain international to play against Galatasaray in the Champions League
The Portuguese coach raised eyebrows during his stint at the Santiago Bernabeu when he controversially dropped Casillas in favour of Lopez.
Carlo Ancelotti has persevered with that selection since replacing the 'Special One' in the Galacticos dugout, but Mourinho insists Casillas is the man to lead Real to la Decima.
"I made the professional decision to leave Casillas on the bench and now it's Ancelotti's decision," Mourinho is quoted as saying in Marca.
"Diego Lopez had a good game against Villarreal but I hope Casillas plays against Galatasaray, I hope he plays well and I hope Real get a good result."
Despite an acrimonious departure from the Spanish capital over the summer, Mourinho insists he still holds his former club in high regards and wants them to do well.
He added: "Unless Real Madrid are playing Chelsea, I always want them to win and wish them all the best."