Mikel Arteta caused a shock when he named his team for the north London derby on Sunday afternoon.
Arteta has now confirmed that the Gabonese striker was dropped for disciplinary reasons.
"He was going to start the game but we had a disciplinary issue. We have drawn the line and we move on. He's on the bench," he said on Sky Sports.
"Obviously we keep that internal," he added when pressed on his reasoning. "We have a process that we have to respect for every game.
"It's a decision made after evaluating the whole values and what he's done and that's it.
"We've got other players that have played and been in the team recently quite a lot.
"There are a lot of players that are willing to play and deserved the chance so I'm comfortable with that."
Watch his interview below:
Wow. What a big story that is. The fact that Arteta has dropped his captain before Arsenal's biggest game of the season suggests that Aubameyang did something quite serious.
Arsenal's starting lineup for the game is as follows:
Leno, Cedric, Luiz, Gabriel, Tierney, Partey, Smith-Rowe, Saka, Odegaard, Xhaka, Lacazette
The onus is now on Lacazette to provide the goals up front.
Freddie Ljungberg was working as a pundit on Sky and gave his thoughts on Aubameyang being left out.
"The only thing I can think about is maybe he has been late or something, because you still keep him on the bench it can't be that bad," he said, per Evening Standard journalist Simon Collings.
It will be interesting to see whether Aubameyang plays any part in the game.