Real Madrid will sign a goalkeeper next summer, at least according to most reports coming from Spain after the CAS decided to grant Los Blancos permission to register new players then.
Thibaut Courtois will be Madrid's priority, per Onda Cero and AS, and even though his contract with Chelsea expires in 2019, people within the club believe that the Belgian goalie would be more than willing to leave the London-based club and play for Madrid.
Courtois is still 24 years old, so he would be an ideal long-term option for Los Blancos, given that both Keylor Navas and Kiko Casilla are 30 years old. Madrid tried to solve that issue by signing David De Gea in the summer of 2015 but the paperwork couldn't be completed in time to register the player. Navas ended up winning the Champions League title in his first season as an undisputed starter for Real Madrid, but it seems that Los Blancos are still looking for a star goalkeeper and they think Courtois is the right man for the job.