Arsenal interim manager Freddie Ljungberg says he "will deal with" Mesut Ozil after the midfielder reacted angrily to being substituted.
The German threw down his gloves and kicked them away when he was taken off in the 3-0 loss to Manchester City.
The incident came hours after the club distanced themselves from Ozil's views following a social media post about the treatment of Uighur Muslims in China.
"How he reacts is up to him and we will deal with it later," Ljungberg said.
"I'm here on a day-to-day basis but of course we want players [to act] in the right way. I wanted more energy in the team."
Ozil, 31, was booed by his own fans as he walked off the pitch to be replaced by 19-year-old Emile Smith Rowe after 59 minutes of Sunday's game.
Ljungberg, who was assistant coach under former Gunners boss Unai Emery, was appointed as interim manager following the Spaniard's departure in November.
There has been no decision made by the Arsenal board about a replacement, with Carlo Ancelotti, Nuno Espirito Santo and Mikel Arteta all linked with the job.
"I've said to them [the board] they need to make a decision," Ljungberg told Sky Sports.
"We are here to help and the staff are trying to chip in, but a decision has to be made so we can have the same resources as other clubs.
"When I say that, they say I have to wait and see."
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Former Premier League striker Chris Sutton, who was in the commentary box at Emirates Stadium for BBC Radio 5 Live, said: "Ozil is not very happy and I understand the frustration but I don't think he should be doing that. It's dissent to his manager - he's saying 'don't bring me off'."
Sutton said the nature of the Gunners' performance - they were 3-0 down after 40 minutes after a Kevin de Bruyne double and a goal from Raheem Sterling - showed Arsenal need to act quickly to resolve their managerial situation.
"Manchester City strolled through the game and it was far too easy," he added.
"There have to be questions asked about Ljungberg now - they are worse than under Emery and they are going backwards.
"They need to make some decisions quickly and put Ljungberg out of his misery. He looks like a rabbit in the headlights.
"Get someone in who has some clout. The decision-makers will have watched the game and seen the difference in class.
"We know Manchester City are good but Arsenal should not have been that bad.
"It was embarrassing. Arsenal made it too easy. Was there passion from Arsenal? Probably - but they just are not that good.
"How low is Freddie's bar? That's why they have to get someone in who has some credibility."