Real Madrid midfielder Aurelien Tchouameni could miss up to two months with a foot fracture, Spanish reports said on Sunday.
The France international presumably sustained the injury during La Liga leaders Madrid's 2-1 Clasico win at Barcelona on Saturday, although he was not substituted during the game.
Madrid did not specify the length of Tchouameni's expected absence in a statement Sunday but said he has suffered "an incomplete stress fracture in the second metatarsal of his left foot".
Tchouameni's absence will allow his compatriot Eduardo Camavinga more chances to play in midfield.
Madrid currently have goalkeeper Thibaut Courtois and defender Eder Militao out long-term.
Tchouameni is expected to miss the rest of Los Blancos' Champions League group stage campaign but could return before the Spanish Super Cup in January.