Arsenal manager Mikel Arteta dropped Pierre-Emerick Aubameyang for Saturday's Premier League clash against Southampton after a "disciplinary breach" by Gabon forward.
Club captain Aubameyang was not among the substitutes at the Emirates Stadium as France striker Alexandre Lacazette took the armband instead.
It was reported that Aubameyang's punishment came after he failed to report for a training session on Friday.
In a pre-match interview on Arsenal's Twitter account, Arteta said of Aubameyang's absence: "Unfortunately (it is) due to a disciplinary breach. We've been very consistent, no negotiables, and he's not involved today."
Asked if it could be a longer-term ban, he added: "It starts today. It's not an easy situation, a situation we want, to have our club captain in that situation."
Aubameyang is without a goal in his last six Arsenal games and has netted just seven times in all competitions this term.
The 32-year-old played for just five minutes as a substitute in Arsenal's 2-1 defeat at Everton on Monday.
His last start came in the 3-2 loss at Manchester United on December 2, when he was taken off in the 79th minute even though Arsenal were chasing an equaliser.
It is not the first time Aubameyang has been left out of Arteta's squad over disciplinary problems.
After the 2-1 win over north London rivals Tottenham in March, it was revealed Aubameyang had breached pre-match protocols by arriving late to the club's London Colney training ground.
"He was going to start the game, we had a disciplinary issue, we've drawn the line, we move on," Arteta told Sky Sports at the time.