Manchester United are close to finalising an £86m ($107m) move for Atletico Madrid forward Antoine Griezmann, according to a report.

Citing sources close to Griezmann, the Manchester Evening News claims that a big money summer move for the 26-year-old from the Spanish capital to Old Trafford is now a formality, even though the France international has been coy when questioned about his future.

Jose Mourinho reportedly believes that Griezmann's signing will transform his side next season and even pondered making a move for him in the January transfer window.

The report comes a day after Atletico manager Diego Simeone admitted he would be powerless to prevent Griezmann from leaving the Vicente Calderon if a club triggered his €100m release clause.

Griezmann signed a new contract to stay at Atletico until 2021 last June after getting assurances that Simeone would stay at the club.

"I spoke to him in the summer holidays, we spoke a lot and he stayed," Simeone was quoted as saying by ESPN.

"He told me that he would stay if I stayed. He then spoke to his agents to sign the documents."

Antoine Griezmann
Atletico Madrid's Antoine Griezmann is reported to be Manchester United's prime summer transfer target Getty Images

Simeone added that he would not stand in the way of Griezmann if the striker told him he wanted to leave Atletico in the summer.

"Griezmann would never allow me to demand of him to stay. I didn't do it with [Diego] Costa and with [Radamel] Falcao.

"The players that have given me their lives, I obviously accompany them in the decisions that they take. What is clear is that as long as [Griezmann] stays, the team and the club will continue to grow."

Griezmann insisted in an interview last week that he intended to stay at Atletico next season.

"Right now I don't see myself at Barcelona or Real, or anywhere else," he told French daily L'Equipe.

"I have no intention of leaving Atletico Madrid, for Paris Saint-Germain, China, the USA, Russia, or elsewhere."