Fonte insists the Juventus star has "always left the door open" for his former club.
"I know he loves Madrid, that's for sure," Fonte told talkSPORT.
"It's clear that he loves the club itself, it's one of the biggest clubs in the world, if not the biggest.
"He's left many, many friends there and he's always left the door open.
"So I wouldn't be surprised if he goes back to Real Madrid."