The 21-year-old, who helped Monaco reach last season’s Champions League quarter-finals, has been targeted by Atletico as they look to replace Turkey international Arda Turan, who joined Barcelona on Monday for a fee that could reach ??29m.
Sources indicated that Carrasco will sign a five-year deal at the Vicente Calderon after passing a medical in the Spanish capital.
The same AFP sources claim Atletico will pay an initial fee of ??10.8m on top of which will be added bonuses, including 25 per cent of any future sell-on fee.
The right-footed left-winger broke into the full Belgium squad last season and scored six goals to help the principality club finish third in Ligue 1.
Atletico chief executive officer Miguel Angel Gil Marin was in Monaco on Thursday evening to finalise the deal and also discuss the possibility of a move for Carraso’s team-mate, Tunisian centre-back Aymen Abdennour.
Monaco have already sold France midfielder Geoffrey Kondogbia to Inter Milan for a reported 35 million euros this summer, while veteran forward Dimitar Berbatov has been released.
Another forward, Valere Germain, has been loaned to Nice and midfielder Delvin Ndinga was loaned out to Lokomotiv Moscow on Friday.
Monaco, however, are close to completing deals to sign Lille’s Malian youngster Adama Traore, one of the stars of the recent U20 World Cup, and Portuguese winger Ivan Cavaleiro from Benfica.
Atletico, meanwhile, are hoping to make their second major signing in a matter of days after Argentine forward Luciano Vietto joined from Villarreal for a reported 20 million euros to help plug the gap left by Juventus-bound Mario Mandzukic.