Lucas Vazquez has suffered a fractured big toe in his left foot, Real Madrid have confirmed.
Vazquez sustained the injury when he dropped a weight during a gym session, according to reports in Spain.
Madrid, who host Real Sociedad on Saturday, have not specified a timeframe for his recovery.
The 28-year-old missed matches against Mallorca and Galatasaray in October due to a calf problem.
"Following the tests carried out today on our player Lucas Vazquez by the Real Madrid medical department, he has been diagnosed with a fracture to the distal phalanx in his left hallux," read a club statement.
"His recovery will continue to be assessed."
Vazquez has made seven LaLiga appearances this season, starting four times and scoring once.
Madrid are level on points with Barcelona but trail the leaders on goal difference.