Real Madrid say forward Lucas Vazquez and midfielder Mateo Kovacic will be sidelined for an undetermined period because of injuries sustained during the Club World Cup.
Madrid issued the medical reports on Thursday, 11 days after the team defeated Japanese side Kashima Antlers 4-2 in extra time in the tournament final.
Vazquez, who played 81 minutes of the final, has a muscle injury in his right leg.
Kovacic twisted a ligament in his left ankle while playing as a substitute in the closing minutes.
Real Madrid won the FIFA Club World Cup for a second time after overcoming Japan's well-organized and dangerous Kashima Antlers side. Cristiano Ronaldo scored a hat trick, with his first taking the game to extra time and, subsequently, two more that sealed the title. Earlier, after Karim Benzema opened the scoring, Kashima hit back to take the lead with goals either side of half time through Gaku Shibasaki.
Madrid dug deep to beat a determined rival, who had the benefits of home advantage;...