However, that may not be to travel to Manchester, with FC Barcelona favourites to sign Griezmann and Paris Saint-Germain also linked. Griezman felt he couldn't leave the club at a time when they were unable to replace him.
However, the France global instead chose to commit his future to Atletico by signing a new long-term deal after the Court of Arbitration for Sport (Cas) upheld their Federation Internationale de Football Association transfer embargo.
"Of course Griezmann will be able to leave at some point, as Diego Costa, Diego Ribas and Arda Turan have gone", Simeone told French sports daily L'Equipe.
Speculation regarding a potential move away from Diego Simeone's side have continued since October, when Mundo Deportivo reported that Barcelona were ready to battle United for his services.
Griezmann is midway through that one additional season, and could leave in summer.
"We managed to make Griezmann better, there is no doubt about it".More news: Police Shoot Knifeman at Amsterdam's Schiphol Airport, Building Evacuated
"I don't speak about players", he said.
"I love my players a lot and I love to see them grow. I love them growing up, I'm not ungrateful", Argentinian Simeone said.
"In January players can come in, players can leave".
Griezmann has scored seven goals in 18 matches in all competitions this campaign, having netted at least 25 times in each of the past three seasons.
"I know that he needs to grow".
At a news conference on Friday, Simeone suggested that Griezmann would return from a week out with a minor hamstring problem to start in Saturday evening's La Liga game at home to struggling Alaves.