Griezmann has been linked with a move to United at the end of the season.
Balague says the Red Devils and Manchester City had a bid rejected for him last summer.
But they could be successful if they went in again this year.
“My understanding is Griezmann is happy with life under Diego Simeone and rejected approaches from both United and City last summer,” Balague told Sky Sports via Daily Star.
“However, Atletico will consider a huge offer and United are still interested.
“What can be said for sure is Griezmann has not signed for anyone at this stage.”
Balague says Griezmann’s versatility will be a big reason why Jose Mourinho will want to take him to Old Trafford.
“This year at Atletico he has already played in six different positions,” he added.
“Mourinho could use him on the flanks knowing he will track back.
“He can also use him as a striker partner for Ibrahimovic, or as a lone striker.
“It will take a huge offer and there is no guarantee he will agree to leave the Vincente Calderon.”