71st-minute substitute Thibaut Courtois left Belgium's World Cup quarterfinal loss to Spain in tears after hurting his thigh, then said the pain was in his quadriceps.
Courtois said he could still stay in goal but struggled with long kicks, and coach Rudi Garcia said he removed the keeper because he was not 100% and Belgium did not want to worsen the injury.
Four saves from Courtois had kept Spain largely in check before his exit, but replacement Senne Lammens spilled a shot that Mikel Merino converted in Belgium's 2-1 elimination.
Real Madrid now await tests on the 34-year-old, whose similar right-quadriceps issue last season sidelined him for nearly seven weeks and could again threaten the start of 2026-27.