The Scotsman caused injury to Bale's ankle in a tackle during a pre-season game in Baltimore yesterday and Walker suggests that his actions came about because he is envious of the type of player the Welshman is.
"The reason for it is simple - he is jealous as Gareth is such a good player. He did him at our place last year when he was sent off," said Walker.
"It just keeps coming up that he doesn't really like him. Players shouldn't hate Gareth, they should appreciate playing against a player like him.
"They could actually learn from him, rather than kick him. He's a great player."