Real Madrid's French striker Karim Benzema had to leave at the half hour mark during the Champions League match against Celtic Glasgow on Tuesday, complaining of his right knee.
The severity and origin of his injury are difficult to determine, the center-forward not having been the victim of any intervention by an opposing player or involved in any contact which would explain it.
But from the 26th minute, after a hand raise from Thibaut Courtois, for a ball comeback after an opposing corner, he started limping after passing the ball.
He tried to carry on, bending his knees in stoppage time, but he was obviously hampered in his movements.
Carlo Ancelotti then decided to replace him by bringing in Eden Hazard in his place, while the score was still 0-0.