Renato Corsi warns Real still must complete negotiations for the youngster, who will be with River for this weekend's Copa Libertadores second-leg clash with Boca Juniors.
"With the suspension of the River-Boca match, the two leaders have not yet been able to speak. Real Madrid has been very correct towards us whether it be me or my partner.
"Both clubs were in talks at the time of the final. But with what happened, things are dragging on. In Madrid, they will start discussions in the coming days."