Real Madrid striker Karim Benzema could face at least a month on the sidelines after limping off during Saturday's 1-1 draw with Levante.
The 29-year-old lasted less than half an hour at the Bernabeu before being withdrawn with a hamstring injury as Madrid dropped points for the second home game in a row.
Early estimations suggest that Benzema could be out of action for between four and six weeks, which would see him miss a substantial chunk of Madrid's La Liga and Champions League title defences.
Los Blancos have already been without Cristiano Ronaldo for the last four matches due to suspension, although the club's all-time leading goalscorer is able to return during the Champions League tie with APOEL in midweek.
Benzema's absence could see Gareth Bale return to the fold after the Welshman was left out of Zinedine Zidane's starting lineup against Levante.