The former Wales international, who has experience of high-profile moves abroad after he swapped Merseyside for Juventus in 1987, believes the 24-year-old must embrace the Spanish culture and language.
GARETH BALE LATEST
Gareth Bale is 50/1 with William Hill to be the top scorer in La Liga
“Also you have to learn the language. That will definitely be needed. It took me six months to learn that.
“When you’re a player you think that the football is all that matters. But small things like not knowing the language do affect your performance on the pitch.”
Ahead of Bale’s potential debut against Villarreal, Rush believes there are question marks over the former Tottenham man's fitness after he missed much of Spurs' pre-season campaign.
“The bigger issue for Gareth on the pitch is his fitness,” Rush added.
“He hasn’t played for a bit and you do need at least four games to get match fitness. You can make mistakes playing for Wales and get away with it. You won’t get away with it playing for Madrid.”