World Cup-winning midfielder Mesut Ozil has been left out of Arsenal's Premier League and Europa League squads, and said on Wednesday "loyalty is hard to come by nowadays".
Gunners manager Mikel Arteta took responsibility, saying he had "failed" with Germany playmaker Ozil, and that his exclusion was purely "a football decision".
However, some Arsenal fans have pointed to his comments in December 2019 about the mistreatment of Uighur Muslims in China and suggested a link to his current exile.
In his social media statement on Wednesday, 32-year-old Ozil wrote: "I will continue to train as best as I can and wherever possible use my voice against inhumanity and for justice."
So what is behind the China suggestions?
What is the background?
In 2018, a BBC investigation revealed evidence that about a million people - mostly from China's Muslim Uighur community - were thought to have been detained without trial in high-security prison camps.
Last December, Ozil, who is Muslim, released a social media post calling Uighurs "warriors who resist persecution" and criticising both China and the silence of Muslims in response.
Arsenal distanced themselves from midfielder Ozil's comments, saying the club is "always apolitical as an organisation".
China has consistently denied mistreating Uighur Muslims in the country and says they are being educated in "vocational training centres" to combat violent religious extremism.
China's foreign ministry spokesman said Ozil had been "deceived by fake news" before making his comments.
Has he played for Arsenal since his original comments?
Ozil had fallen out of favour under previous manager Unai Emery before returning to the side under interim boss Freddie Ljungberg at the start of December 2019.
After Arteta's appointment as permanent manager later that month - the same in which Ozil made his original comments - the German started all 10 of the club's Premier League games before the coronavirus pandemic forced a three-month suspension in March, but he has not been seen in an Arsenal shirt subsequently.
Since joining from Real Madrid seven years ago, Ozil has scored 44 goals in 254 appearances in all competitions for the Gunners.
He said on Wednesday: "I'm really deeply disappointed by the fact that I have not been registered for the Premier League season for the time being.
"Upon signing my new contract in 2018, I pledged my loyalty and allegiance to the club that I love, Arsenal, and it saddens me that this has not been reciprocated.
"I've always tried to remain positive from week to week that there's maybe a chance to get back in the squad soon again. That's why I kept silent so far."
'Ozil should look at the mirror himself'
European football expert Guillem Balague:
"I find the suggestion that Ozil has been moved aside for his political stance an intentional distraction and very convenient. He has played and has been called up since he made his comments on China and the Uighur Muslims. You have to look at the bigger picture [in footballing terms].
"Why have the last two managers struggled to find a way to fit him in? He is talented, no doubt, but talent is not enough in the elite.
"You have to be committed, interested, follow instructions on the pitch, work hard in training and in the games, with and without the ball, have faith in the group and in the leader… all that is necessary.
"It is very easy to influence Arsenal fans by suggesting there is a hidden agenda here, but why would two managers go against doing the best for their own teams by leaving Ozil out?
"Would it be by any chance that they needed to bring some standards which Ozil did not match? I have the impression Ozil should look at the mirror himself and be honest with what he sees.
"Ozil is not able to impact games on a regular basis and now the manager feels that it is best for the group to leave him out of the Premier League and Europa League squad."
So why the China theory?
Following his exile, some Arsenal fans suggested Ozil has been cast aside because of his support for the Uighur Muslims.
The phrase 'Muslims in China' was trending on social media immediately after Wednesday's statement, and some have expressed concerns at Arsenal's failure to back their player.
When contacted by BBC Sport, Arsenal reiterated Arteta's response, insisting it was "a football decision and that alone".
Earlier this month, Ozil raised a political point on social media once more, calling for a "resolution" in the ongoing violent conflict between Azerbaijan and Armenia regarding the Nagorno Karabakh region.
His contract expires at the end of the season and he will end his time at Emirates Stadium eligible only for the under-23 side this season, while picking up a reported £350,000 a week in wages.
Ozil's Germany career also ended in controversy, quitting international football in 2018 citing the "racism and disrespect" he has faced in Germany over his Turkish roots.
Former Arsenal striker Ian Wright said he was "gutted" Ozil will not get the chance to play and called the situation "sad", while ex-Gunners' midfielder Jack Wilshere added: "He is one of the best players I have played with and it must be so frustrating for him. What a great player.
"It is a tough time for him but I am sure, if it is not at Arsenal, he still has a lot to give as well."
What has Ozil's agent said?
Dr Erkut Sogut is Ozil's agent and has contradicted Arteta's claim that his client has been treated fairly.
"Arsenal fans deserve an honest explanation, not [Arteta] saying, 'I failed Ozil'," Sogut told ESPN.
"You didn't fail Ozil. You failed to be fair, honest and transparent and treat someone with respect who has a contract and was loyal all the time."
Sogut claimed he had spoken to "at least" five of Ozil's team-mates "who say he is training great" and "cannot understand why he is left out".
On the issue of the social media post about Uighur Muslims in China, Sogut says Ozil expected "more support from the club".
"Imagine a football player comes out and says 'this is inhumane'. Is that politics or empathy?" he added.
"Mesut cannot speak now because of confidentiality, but one day he will, and we'll see what people think."