Arsenal manager Arsene Wenger revealed on Saturday that Spanish midfielder Santi Cazorla will be sidelined for several weeks due to an ankle injury.
Cazorla missed the 3-1 Premier League win at Sunderland because of the problem and Wenger, whose side face Marseille in the Champions League on Wednesday, later admitted the 28-year-old may not be back before the next international break in October.
"Cazorla has an ankle problem and he will be out for a few weeks. I don't think he will play before the next international break," Wenger said.
The Gunners boss also has concerns over French striker Olivier Giroud, who scored his side's first goal at the Stadium of Light before limping off late on with a knee injury.
"That's my worry after the game because we are very thin at the moment. He has a knee problem," Wenger added.