This rules him out of this weekend's match against Espanyol but gives the club cautious optimism about his availability for the Clásico against Barcelona on 10 May.
The official club statement read: "Following tests carried out today on our player Kylian Mbappé by the Real Madrid Medical Services, he has been diagnosed with an injury to the semitendinosus muscle of his left leg. His recovery will be monitored."
The semitendinosus is one of the three hamstring muscles in the back of the thigh, and an injury to it typically requires between two and four weeks of recovery — though severity varies. With El Clásico scheduled for 10 May, almost two full weeks remain, making a return feasible if the injury is at the milder end of the spectrum.
The news represents a significant relief for Real Madrid after immediate speculation following Mbappé's withdrawal from the pitch in the 81st minute on Friday suggested a more serious problem. His previous injury this season — a left ankle ligament issue in October — kept him out for almost four weeks.
Mbappé is Real Madrid's top scorer this season with 29 goals across all competitions. His absence from the Espanyol game comes at a point when Barcelona need only a draw to confirm the La Liga title mathematically, making the Clásico a potential title party rather than a championship contest.