Arsenal winger Theo Walcott will miss the Champions League home game against Montpellier on Wednesday because of a shoulder problem.
England international Walcott picked up the injury during the Gunners' 5-2 win over North London rivals Tottenham on Saturday, but played through it and scored his side's fifth goal.
However, Arsenal manager Arsene Wenger said Walcott had not trained on Tuesday and would be undergoing a scan to determine the extent of the problem.
Andre Santos is also unavailable, but Gervinho and Kieran Gibbs both make returns to the squad.
Wenger went on to explain the strategy he has vowed to adopt over Walcott's contract wrangle, saying he was willing to lose the England striker on a free next summer to retain his services for the rest of this season.
"There's a risk [of losing him for free], but this is a risk we are ready to take," Wenger said.
"A successful season is more important for us than this risk that is only a financial risk, apart from the losing the player. If we sell him, we lose him anyway. I believe that we started the season with this squad and we want to finish the season with this squad.
"I don't know if you call the strategy high-risk, but it is just my opinion. What is important is what we achieve together for the season. To do that... I think Theo is a big part of that."