Coach Zinedine Zidane confirmed the 21-year-old would be missing from Wednesday night's game against Apoel Nicosia during a press conference, although did not divulge in details of how the affliction was caused.
"He has a pimple on his leg which means he cannot lift his sock," the Frenchman said between laughs.
Going into further detail, Spanish newspaper ABC has reported the attacking midfielder's hair got infected thanks to a razor.
The youngster has enjoyed a flying start to the season, scoring four goals in Madrid's opening six games.
Zidane will be hoping Asensio can return for Sunday's game against early La Liga table-toppers Real Sociedad.
But for now the coach's attention will turn to events at the Santiago Bernabeu on Wednesday night where Madrid host the Cypriot champions.
Madrid, looking to win their third consecutive European crown, will welcome back Raphael Varane from injury, Luka Modric, Casemiro and Keylor Navas who were all rested in the 1-1 draw with Levante and Cristiano Ronaldo who has missed domestic competition through suspension.
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