Laurent Koscielny: (Hamstring) out three weeks

Koscielny will be out for Sunday's fixture against Manchester United. "He has a hamstring strain, and it looks like it will be three weeks, something like that," manager Arsene Wenger said.

Analysis:

Koscielny's absense will put a real dent into Arsenal's already shaky collection of center backs. Gabriel will slide into his spot in the starting XI alongside Per Mertesacker, but Koscielny has been the steadiest of the bunch and his absence will be felt, particularly against stiffer competition.