Diego Simeone has opened up on the speculation regarding Atletico Madrid's star-player Antoine Griezmann.

The forward has enjoyed a fantastic two seasons that has seen his reputation sky-rocket, and in turn, brought about great interest in his signature.

Manchester United made no secret whatsoever of their desire to bring Griezmann in last summer, and seemed incredibly close, only for the Frenchman to commit to Atletico for at least one more season.

The change in heart came after Griezmann felt he couldn't abandon the side at a time when they were unable to replace him.

Atletico were given a one-year transfer ban, preventing them from being able to recover from a loss as big as Griezmann's.

That ban is up in January, however, and the speculation around the 26-year-old's future is already beginning to grow.

Diego Costa has already moved back to the Spanish capital and will be able to begin playing again once the window re-opens, leaving Simeone's side with immediate cover should Griezmann go.

And now the Argentinian coach has openly discussed the possibility of moving on - and it might be music to United ears.

"Of course Griezmann will be able to leave at some point, the same way (Diego) Costa and Arda Turan were allowed to leave," Simeone told l'Equipe.

"I love my players a lot and I love to see them grow. I am not ungrateful.

"If a player comes to me and says: 'Coach, I have a once in a lifetime chance to play for a certain team, I want to leave'.

"If he did all he could for me as Griezmann does, I'll say it's no problem. I know that he needs to grow."

Simeone opening the door for a move could create a bidding war as early as January - even if Atletico will be reluctant to sell half-way through the season.

Man United are certainly interested, but there have been strong reports that Barcelona will bid if a move is possible.

The Catalonian's are still searching for their Neymar replacement, and a player with the stature of Griezmann would be just about as good as it gets - and a remarkably simpler transfer than that of summer target Philippe Coutinho.

Not that they are the only two. Paris Saint-Germain and Real Madrid have also been linked with the player who finished 3rd in the 2016 Ballon d'Or.

This one could be the story of the transfer window.