Mikel Arteta has alluded to "internal issues" to explain the decision to bench Matteo Guendouzi on Thursday.
Arsenal enter Thursday's match on the heels of back-to-back defeats, returning to Premier League play with a 3-0 battering at the hands of Manchester City before falling 2-1 to Brighton in their second match of the restart.
That Brighton match was not without controversy, though, with much of that controversy centring around forward Neal Maupay.
The Brighton forward became the target of Arsenal frustrations after a collision with goalkeeper Bernd Leno, one which forced the Arsenal goalkeeper out of the match and out of the Gunners lineup for several weeks.
With just moments left in the match, it was Maupay who scored Brighton's winner, prompting a confrontation between Arsenal players and the French striker.
During that confrontation, Guendouzi was seen grabbing Maupay, with reports emerging that Guendouzi had been bragging about his wages compared to those of Brighton's players.
Maupay alluded to those rumours after the match, stating that Arsenal's players lacked humility, although he didn't single out Guendouzi by name.
The Football Association confirmed earlier this week Guendouzi would face no punishment for his clash with Maupay.
In the wake of the reports, Guendouzi did not start Thursday's clash with Southampton, with Arteta turning instead to the likes of Granit Xhaka and Dani Ceballos in the midfield.
When asked by Sky Sports for the reason behind the midfielder's exclusion, Arteta said: "Squad management. Whatever internal issue we have, we deal with it privately.
"The needs of the team and the football club are always the same - put the best players on the pitch who are 100 per cent focused on winning the game."
In the run up to the match, Arteta said that Guendouzi must learn to conform to Arsenal's values while adding that he prefers to deal with issues in behaviour on a personal level.
Arteta did acknowledge, however, that some players must remain a bit rough around the edges as that's a quality that defines how they play.
Guendouzi, who joined Arsenal from Lorient in 2018, has made 82 appearances for the club since making the move from Ligue 1.
This season, the 21-year-old has made 34 appearances in all competitions, including 24 in the Premier League.