Griezmann revealed his desire to leave Atletico for a new challenge just before the end of the 2018-19 campaign, despite signing a new contract last June.
When Griezmann agreed his new deal, he announced his decision in a documentary-style video, putting an end to prolonged speculation linking him with Barcelona.
He was not at his sparkling best for Atletico this season, however, scoring 15 times in 37 league matches, a significant decline from the haul of 19 in 32 games the previous term.
Links to Barca have gone quiet in recent weeks, with Atletico insisting it has had no contact from anyone at the league champion, though Gil Marin is certain a move to Camp Nou will materialise for the Frenchman.
"I know where Griezmann is going to play: at Barcelona. It is known since March," Gil Marin told Movistar.
Griezmann is contracted to Atletico until 2023 and is reported to have a €120million release clause.