Arsenal boss Mikel Arteta has revealed Pierre-Emerick Aubameyang wasn't named in the club's matchday squad to due personal matters.
Arsenal made seven alterations from their 3-0 Premier League win over Newcastle on Monday night. Eddie Nketiah was handed a start against Southampton with Alexander Lacazette dropping to the bench while Aubameyang missing out completely.
"He had a personal matter in the last few hours and we had to send him back," Arteta explained.
New signing Mat Ryan was named on the bench as Bernd Leno continued in goal, while Hector Bellerin and Gabriel Magalhaes came into the back four.