Real Madrid are close to completing the signing of River Plate star Franco Mastantuono, sources have told ESPN, with the playmaker expected to arrive in August, after playing for River at the Club World Cup. Madrid will pay a €45 million fee for Mastantuono, sources said -- although the structure of that payment is yet to be finalised -- and the player will sign a six-year contract until 2031. ESPN reported on Wednesday that a Madrid representative was in Buenos Aires looking to push through a deal for the Argentina international, 17, amid competition from Paris Saint-Germain. Mastantuono favoured a move to the Santiago Bernabéu, and his camp had put talks with PSG -- which were advanced -- on hold as they waited for Madrid to follow through on their long-term interest in the player. Sources told ESPN that Madrid have now accepted that Mastantuono will join them in August -- he turns 18 on Aug. 14 -- meaning he will play for River at the Club World Cup in the United States, in accordance with the midfielder's wishes, and to help ease his departure. Madrid and River are now working on finalising the details of the agreement, including the form of payment, although that is not believed to represent a major obstacle. New coach Xabi Alonso has given his approval for the move for Mastantuono. Madrid believe that, following the departure of veteran Luka Modric this summer, the Argentinian represents an immediate solution in midfield, valuing his vision, and precocious threat from set pieces. Madrid have also received positive reports about the player's personality and behaviour in recent months, sources said. Mastantuono made his debut with Argentina senior team on Thursday night against Chile in the South American qualifiers. The teenager entered from the bench in the 84th minute in Argentina's 1-0 win, becoming the youngest player to ever represent the 'Albiceleste' in an official match.