Atletico said in a statement on their official website: “Atletico de Madrid and AS Monaco have achieved a preliminary agreement over the transfer of Thomas Lemar to our club.
“Over the next days, both clubs will work to close the agreement for the definitive transfer.”
The France international, currently in Russia with Les Bleus for the World Cup, joined Monaco in 2015 from Caen and made his international debut in November 2016.
Monaco echoed Atleti’s statement on their official Twitter feed, saying: “AS Monaco and @Atleti announce that they have found an agreement in principle for the transfer of Thomas Lemar.
“The two clubs will continue to work in the coming days in order to find a definitive agreement.”
Fellow France forward Griezmann says he has decided on his future – but has refused to say whether he will leave Atletico this summer.
With ongoing speculation linking him with Spanish champions Barcelona, Griezmann had said he would confirm his position before France’s World Cup opener against Australia on Saturday.
However, at a national team press conference in Russia, the 27-year-old repeatedly laughed off questions regarding a potential move before claiming he has made up his mind where he will be playing next season.
“The decision has been taken but it is not the time or the place to talk about it,” he said.
“I am very sorry, I know you have all been waiting but I will not give my decision today.”
It is the second successive summer that Griezmann has been the subject of speculation over a big-money switch away from the Rojiblancos.
Last year it was Manchester United who looked to be leading the chase for his services only for Griezmann to end up signing a one-year contract extension with Atletico, tying him to the club until 2022.
His refusal to answer questions on Tuesday means links with Barcelona are sure to continue until any formal announcement is made by either club.
Since joining from Real Sociedad in 2014, Griezmann has scored 112 goals in all competitions for Atletico and finished each season as the club’s top scorer.
He also helped Atletico reach the 2016 Champions League final and scored twice as they beat Marseille 3-0 in last month’s Europa League final.
The La Liga giants have announced that the former Real Madrid Castilla coach will now take over the senior squad.
The move comes as a surprise, with Lopetegui not featuring prominently among the host of managers linked with the role since the departure of Zinedine Zidane days after Madrid’s 3-1 victory over Liverpool in the Champions League final.
Lopetegui, who has been in charge of the national team for the past two years, has agreed a three-year contract at the Bernabeu.
Recalled Italy striker Mario Balotelli has been contacted by Marseille about making a summer switch once his productive spell at Ligue 1 neighbours Nice comes to an end, according to reports.
Balotelli, 27, experienced the most-prolific season of his headline-grabbing career in 2017/18 when he struck 26 times in 38 matches.
But his one-year contract at Les Aiglons expires on June 30 and there is no sign of a renewal.
L’Equipe has stated that l’OM’s desire to get a new centre forward has drawn them towards the ex-Internazionale, Manchester City and AC Milan attacker.