Thibaut Courtois leaves the World Cup quarterfinal against Spain with quadriceps and hip muscle discomfort and is substituted at 71 minutes after reporting pain to medical staff during a hydration break.Senne Lammens replaces Courtois and misplays a long clearance that allows Mikel Merino to score the decisive goal as Spain wins 2-1, prompting debate over the timing of Rudi García's substitution.Medical staff will assess the extent of Courtois's injury, he plans to rest to recover and his future with the Belgian national team is uncertain while the Belgian Football Association faces scrutiny over goalkeeper depth.