"He won't play anywhere else, I don't think, but you never know," Barnett said. "I certainly don't think he'll come back to play in England but you never know."
Barnett made headlines earlier in the summer for his open criticism of Bale's Real Madrid teammates. At the time, he told Telegraph Sport that the ex-Tottenham Hotspur man was being shunned by his fellow players.
“Real have to work with Gareth and pass the ball to him more," he said. "Give him more of the ball and let him show everybody what he’s good at. He’s going to be the best player at Real Madrid when his team-mates work with him and help him. Hopefully Real will come to terms with this."
Amid the unrest in Madrid, his client was strongly linked to Louis Van Gaal's Manchester United throughout the summer – by the Daily Mail, among others. However, despite criticism of the Welshman's performances in Spain last season, Barnett now says Real Madrid only have the best intentions for Bale moving forward.
"He's at the biggest club in the world and he's going to be the biggest player in the world," Barnett added. "Real Madrid have made it very clear he is their main player, or will be, and that's where it is going to stay. The next few years will be very exciting for him."
The 26-year-old has started the new campaign well for both club and country, after a disappointing one last time out. And if Bale can maintain his level into and beyond the new year, then his potential availability might well be off the table for good.
Not that United should be overly concerned about that as, despite the regular rounds of rumours throughout the recent window, Van Gaal was able to complete deals for Memphis Depay and Anthony Martial - bolstering his options considerably in the final third of the field.