Los Blancos managed to win the 2016 UEFA Champions League with Costa Rican keeper Keylor Navas, but he has not been the same player he once was after having surgery to repair his heel during the past summer. Navas has completed some shaky performances lately like when Madrid suffered a late, surprising 2-1 defeat in Sevilla, so it seems that the goalkeeper spot is one Los Blancos could definitely upgrade next summer.
Courtois is the undisputed starter between Chelsea's sticks, so it will not be easy to sign him away from the London-based club. However, his contract expires in 2019 and would be interested in making his return to the Spanish capital, according to reports from Spain. Real Madrid will need to spend some money if they want Courtois, but he is definitely worth it.