According to Goal's Chris Wheatley, the Gunners have not yet made a move to secure Ozil's signature despite the German being in the final year of his deal at the club, though they did reopen talks with him at the start of the season.
The playmaker enjoys life in London and could be open to staying at the club, but he also reciprocates the interest from United and Barca, the latter of whom can begin talking to him in January.
Ozil has been in and out of the team in recent weeks dealing with a knee inflammation. He's an often divisive figure; the Daily Telegraph's Matt Law expressed his belief the Gunners are better off without the 28-year-old:
The midfielder has faced a great deal of similar criticism during his time in north London, with his attitude and mental strength repeatedly questioned.
Former Arsenal defender Martin Keown lent his voice to that criticism while speaking on BBC 5 live Sport:
However, while Ozil has not always inspired confidence during his time with Arsenal—there remains a perennial question mark over his performances in the most important games in particular—he is perhaps unfairly scapegoated at times.
Along with Alexis Sanchez, the German has established himself as a key player in the side, and the team evidently struggle if neither are on the pitch, per football writer Daniel Storey:
Ozil may only have played 367 minutes of Premier League football this term, but his numbers are comparable with the division's other top stars, as demonstrated by Arsenal stat account Orbinho:
Indeed, while he has not yet registered an assist, he has created 15 chances in just five appearances, the last of which was just 11 minutes long, per Squawka Football.
There's much he could contribute at Barcelona or United, and as a free transfer, he'd be a low-risk acquisition for either side.
Marca's Chris Winterburn believes he could be a shrewd signing for United:
He may yet agree terms to remain at Arsenal, though, and that would be beneficial to the Gunners.
Losing a player of his calibre for free would be a bitter pill to swallow, and it will make next summer even harder given Sanchez also looks set to leave in the same circumstances.
Keeping him will allow Arsenal to focus more of their resources on replacing Sanchez and avoid the worry of having to adequately compensate for the loss of their two best players.