The 33-year-old right-back, who only recently returned from a long-term ACL injury, sustained the new issue in the same knee during Real Madrid's 2–1 victory over Barcelona in El Clasico on Sunday.
A club statement confirmed the severity of the problem after medical tests were carried out on Monday.
"After the tests carried out on our captain Dani Carvajal by the Real Madrid medical services, he has been diagnosed with the presence of a joint free body in his right knee. Carvajal will undergo an arthroscopy," the statement read.
Spanish outlet El Partidazo de COPE reported that the veteran defender is expected to miss between two and three months of action, ruling him out for the remainder of 2025. A possible return is now being targeted for early 2026.
Carvajal's latest setback is particularly frustrating as it comes shortly after his comeback from a string of injuries that limited him to just seven appearances this season.
He featured in Real Madrid's FIFA Club World Cup semi-final against Paris Saint-Germain before suffering a muscle problem that kept him out for several weeks.
He made his return as a substitute in El Clasico, where he was involved in a post-match incident with Barcelona youngster Lamine Yamal.
Carvajal, who has spent over a decade with Los Blancos and captained them since 2025, will now focus on rehabilitation as Real Madrid continue their pursuit of domestic and European honours without one of their most experienced leaders.
Real Madrid's 2–1 victory over Barcelona might have reinforced their dominance in La Liga, but instead it exposed growing tension between head coach Xabi Alonso and star winger Vinicius Junior.
Barcelona have been handed a major boost after Robert Lewandowski returned to full training ahead of their La Liga match against Elche this upcoming Sunday.
Real Madrid edged Barcelona 2–1 in a high-stakes El Clasico, while elsewhere Mallorca salvaged a draw, Celta stunned Osasuna late, and Rayo grabbed victory in stoppage time.
Villareal moved into third spot on the LaLiga table after beating Valencia whilst Getafe and Espanyol defeated Athletic Club and Elche respectively.
