An Arsenal star had to be substituted after just five minutes against Liverpool after suffering an injury.
William Saliba had to go off after colliding with Liverpool forward Hugo Ekitike, with Cristhian Mosquera coming on at centre-back.
It represents another injury blow for Arsenal boss Mikel Arteta to contend with.
Arsenal went into the game without Bukayo Saka, who suffered a hamstring problem against Leeds last weekend.
Kai Havertz is sidelined with a knee problem that could keep him out until November, while Ben White and Christian Norgaard are also unavailable along with long-term absentee Gabriel Jesus.