Matteo Guendouzi was dropped for Arsenal's trip to Southampton, with boss Mikel Arteta describing the decision as "squad management".
Guendouzi had an altercation with Brighton striker Neal Maupay on Saturday in a match which the Seagulls won 2-1, with Guendouzi appearing to grab his opponent by the throat.
- Southampton 0-2 Arsenal - Match report and highlights
- Guendouzi to face no further action over Maupay incident
Asked about that incident, for which the FA has ruled out any punishment following a VAR review, Arsenal boss Arteta told Sky Sports: "Whatever internal issue we have, we deal with it privately.
"The needs of the team and the football club are the same, putting the best players on the pitch who are 100 per cent focused to win the game."
Arteta reiterated his stance after the Gunners' 2-0 win at St Mary's but hinted that Guendouzi may come back into the reckoning for Sunday's FA Cup quarter-final at Sheffield United.
"It was squad management as I said before," he said of the player's omission. "I will deal with these issues internally. The door is always open and everyone is welcome to jump on the boat."
'He acts like he's a big player and he's not yet'
Speaking ahead of kick-off, Sky Sports pundit Jamie Redknapp questioned Guendouzi's attitude, saying: "He can definitely play, make no mistake. He's got talent.
"He acts like he's a big player and he's not yet. You've got to earn the right to become a big player. I remember the game against Southampton last year; me and Tony Adams did some analysis about him not tracking hard enough.
"At that age, you should be learning the ropes, doing everything you can to become a really good player. A couple of times Arteta has had to leave him out of the squad. It shouldn't be happening and it suggests something is wrong."
Fellow pundit and former Gunner Sol Campbell said: "If you've got good characters at the club, it gets snuffed out and policed; it doesn't start creeping onto the pitch. It gets handled. It doesn't even go up to the manager."
Speaking after Arsenal's defeat to Brighton, Arteta said that his players needed to have better control of their emotions.
"When we show frustration we have to show it in the right way," he said. "Emotionally, we have to control the situations much better."