Barca have been linked with meeting the €100m buyout clause in Griezmann's deal at the end of this season.
And the decision to hand Philippe Coutinho the No14 shirt is seen as a further clue that an agreement has already been settled. Barca's No7 shirt remains vacant after Arda Turan's departure - and is a favourite of Griezmann's.
El Mundo Deportivo says the decision inside Barca has already been made - to meet the Frenchman's escape clause in June.
And with the No7 shirt clear to be inherited, it will smooth negotiations over personal terms with Griezmann, who's marketing and merchandise plans hinge on keeping his current Atletico number.