Gareth Bale has been accused of not being passionate enough and failing to fill Cristiano Ronaldo's boots at Real Madrid.
Bale, 29, who joined Real from Tottenham for £85 million ($112m) in 2013, was tipped to step up to fill the void created by Ronaldo's departure for Juventus last summer.
However, he remains a target for taunts from pundits and fans alike.
Valdano, who managed the Blancos between 1994 and 1996, told the El Transistor de Onda Cero podcast: "Bale has a tremendous class, but then he disappears, he shows less passion than other players."
Valdano questioned the forward's injury record and said Brazilian teenager Vinicius Jnr has done more to soften the blow of Ronaldo's exit.
"Bale is a player who fights against his body, he does not look like a passionate player," he added.
"He came to occupy the emptiness left by Cristiano and he has not, the one who has occupied that empty place is Vinicius."
Valdano, meanwhile, does not understand how Spanish forward Isco has fallen out of favour with manager Santiago Solari, saying: "It is surprising that Madrid renounces a resource like Isco."
But he is full of praise for a rejuvenated Karim Benzema.
The Frenchman, 31, scored twice against Espanyol and Valdano said: "Benzema is in a fantastic moment, he is a silky player, of an exquisite class and the confidence has made him dangerous.
"The whistles have turned into applause and right now he is the greatest value of the team with [Sergio] Ramos and [Luka] Modric.
"Benzema is in the best moment of his career".