Real Madrid boss Zinedine Zidane has admitted that he is 'unsure' of the seriousness of the injury that Pepe suffered in Saturday's La Liga clash with Alaves.

The Portuguese centre-back had to be replaced midway through the first half of Real Madrid's 4-1 win, with Nacho introduced as Los Blancos' injury problems worsened.

Zidane, speaking after the Alaves match, refused to be drawn on suggestions that Pepe, who will undergo a scan on Sunday afternoon, could be facing an extended period on the sidelines.

"Pepe? When we go back to Madrid, we'll do an MRI on him and see the results," Zidane told reporters. "I can't say anything about his recovery time, so the only thing I can do is continue working with all players that are ready and for him to come back as soon as possible."

Manchester United are reportedly preparing a January move for Pepe, whose current Real Madrid contract will expire at the end of this season.