Mikel Arteta doesn't know when to expect Pierre-Emerick Aubameyang back at Arsenal as he deals with a "personal issue".
The Gunners forward pulled out of the squad to take on Southampton just hours before kick-off.
Arteta saw his side go down 1-0 at St Mary's courtesy of a Gabriel own goal.
Aubameyang has rediscovered his goalscoring touch in recent weeks, but his manager insists the most important thing right now is that he fixes his issue.
"I don't know," said Arteta, when asked about Aubameyang's availability.
"He needs to address that issue, we'll see how it evolves.
"We're here and we have to support him and he needs to take the time that is needed because that is a priority at the moment."
The Gabon international had scored in two of his side's last three games.
He may soon be joined at the Emirates by Real Madrid star Martin Odegaard.
The young Dane has been heavily linked with a loan switch to north London with Arteta expecting an update on the situation this weekend.
"Since last night I don't have any news," he said.
"I will probably get a few phone calls today and see where we are with everything."
Arsenal made the somewhat surprising addition of Mat Ryan on loan from Brighton on Friday.
The Australian will serve as back-up to Bernd Leno with the Gunners unable to replace Emiliano Martinez, who left late in the summer to join Aston Villa.
Willian, who joined Arsenal in the summer on a free from Chelsea, was one of the men to cop criticism following the Southampton loss.
It brings into question the club's recruitment with Nicolas Pepe also coming under fire.
Arteta though remains confident that the pair will come good.
"What I am saying is they try to give their best," he said. "You could see how hard they are trying, with more or less quality, but the intention is there and the willingness is there.
