Asensio was replaced by Casemiro in the second half after just coming on for Gareth Bale during the Club World Cup final on Wednesday.
Marco Asensio could only manage 14 minutes in the semi-final of the Club World Cup before his thigh injury flared up and he had to be replaced by Casemiro. He came on after 59 minutes to give Bale a rest, who was himself returning from an injury, but he retired after 73 minutes with visible discomfort in his thigh.
After training in the build-up to the semi-final, Asensio was a surprise inclusion and he was brought on at 3-0 to test the muscle, which he injured against Rayo Vallecano in LaLiga last Saturday. But that proved to be a bad decision. The club have not confirmed the injury's severity but he will likely miss the final on Sunday against Al Ain.
Casemiro returns, selection issues for Solari
Casemiro returned for the first since November when he injured his knee against Celta Vigo and he took Asensio's place. Both Marcos Llorente and Casemiro were deploted in deep midfield with the Spanish midfielder taking the Brazilian's place during his absence.
Santiago Solari has a decision to make now with Llorente barely putting a foot wrong since stepping into the starting role. Casemiro has been a bonafide starter for a number of years now too, which could cause the Argentinian some selection headaches.