Griezmann was expected to join Manchester United this summer, though chose to stick with Atletico out of loyalty after their transfer ban was upheld.
Speaking with Foot Mercato, Spanish pundit Ivan Vargas explained the agreement was only temporary.
"It was like an agreement between him and his club. Because if Atlético really wanted to retain him, they would have increased the amount of his release clause. With this extension, Madrid ensures his presence for an additional season.
"Next year, the club will facilitate his departure, especially if the offer is close to his clause. And if it is abroad, that is to say not to Real Madrid, it will be even better. Both sides are winners."