Mesut Ozil's future at Arsenal looks increasingly uncertain with the club yet to offer an extension on his contract which expires in 2021, sources have told ESPN.

Ozil was informed he could leave the Gunners last summer as relations soured with former Arsenal boss Unai Emery but the midfielder enjoyed a renaissance under Mikel Arteta, starting all 10 Premier League games since the Spaniard took charge in December.

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However, it is understood that revival has not led to a change in stance from the club's hierarchy, who are yet to open talks over prolonging Ozil's stay in north London-- heightening the possibility he could either leave either at the end of this season or on a free transfer once his existing deal expires.

The 31-year-old's £350,000-a-week wage has been a source of controversy almost from the moment he signed it in January 2018.

Ozil then had six months left on his previous agreement and, having already allowed Alexis Sanchez to depart for Manchester United in a swap deal for Henrikh Mkhitaryan, Arsenal were under pressure not to lose their other star name.

The Gunners shattered their wage structure to keep Ozil, a move sanctioned by former chief executive Ivan Gazidis and initially praised in many quarters as a sign of the club's aspirational intent.

However, Ozil's salary has always remained an outlier when compared with the rest of the squad - even today, the next-best earner is Pierre-Emerick Aubameyang on around £200,000-a-week -- and under Emery he became a marginalised figure unable to justify his status as one of the highest-paid players in England.

In an effort to avoid being backed into a corner during contractual negotiations, Arsenal adopted a policy in the wake of Gazidis' departure to sell players who are unwilling to commit their futures to the club before they enter the final year of their contracts.

The situation is different with Ozil, who has not agitated to leave and even previously expressed an interest in staying beyond 2021 but given he turns 32 in October, there are doubts over whether he will remain part of Arteta's long-term plans.

That means the club may look to sell this summer, but interested clubs have in the past found his salary a major obstacle. Inter Milan, AC Milan and Fenerbahce were previously keen but were unable to match his wages. Ozil has also attracted suitors in China but did not show any desire to move to Asia at the time. He has consistently stated in public he aims to see out his contract.

The picture is unconnected with Arsenal's recent pay cut row. Ozil is one of at least three players to reject the club's request for the entire first-team squad to take a wage reduction of 12.5% for 12 months with Arteta insisting during talks that any individual could opt out without fear of future repercussions.

As ESPN reported last week, Ozil wanted to seek further assurances over where the savings -- estimated to be around £20 million -- would be spent and what impact it would have on future transfers. Ozil remains open to agreeing a cut with talks ongoing

There were also questions raised over why they remain the only English club to take a cut rather than a deferral and also over the length of the reduction. Several other clubs have announced deferrals for three or four months.

Arsenal's desire to push for a cut hints at the economic pressures they fear as a result of the coronavirus pandemic. The Gunners currently spend around £230m-a-year on wages with director Josh Kroenke last year describing the figure as "a Champions League wage bill on a Europa League budget".

Removing Ozil from the balance sheet would help ease that picture but it would also bring to an end an association which began in October 2013 when signing from Real Madrid for a then club-record £42.4m fee.

He has gone on to make 184 Premier League appearances to date and in March 2018 became the fastest player to reach 50 assists in Premier League history, a record only surpassed later that year by Manchester City's Kevin De Bruyne.