Ozil would be interested in potentially joining the Liga giants or Jose Mourinho's side, with the Germany international's contract with the Gunners due to expire in summer 2018.
There is, however, still a chance Ozil could remain with Arsenal, despite no offer over a contract extension having yet arrived after talks over a renewal were put on hold back in February.
Ozil, who recently bought a new house in London, is able to sign a pre-contract with a foreign club in January, although it is understood he remains happy living in the capital city where he is settled and has made many close friends.
Reports claiming that the former Real Madrid star has rejected a contract offer in the region of £275,000-a-week are completely false, although both Barca and United are realistic options for the German.
Indeed, both clubs are among the three sides Ozil would be willing to play for aside from Arsenal, with Madrid completing the trio of superclubs.
United have Jose Mourinho at the helm and he knows Ozil well from their time together at Madrid, although a major sticking point in any deal would be the player’s reluctance to move to Manchester.
Barcelona are on the lookout for a new playmaker and, after being rebuffed in attempts to sign Philippe Coutinho from Liverpool, the considerably more affordable option of Ozil presents itself as an attractive proposition.
Real Madrid are unlikely to come back in for their former star but Ozil still has many friends in the Spanish capital and enjoyed the most successful years of his career playing under Mourinho at the Santiago Bernabeu.
Ozil has come under criticism from ex-players and pundits recently, including former Arsenal defender Martin Keown, who said that Ozil didn’t fancy the Europa League trip to BATE Borisov and that he’s "psychologically already left the football club".
Minutes per chance created this season (min 10 chances)
1 Coutinho 17.6
2 Ozil 24.5
3 Sanchez 24.9
4 De Bruyne 25.2
5 Silva 26.2
7 Cesc 26.5 — Orbinho (@Orbinho) October 5, 2017
However, Ozil's absence from the team has been due to a knee inflammation problem, which is why Germany national team coach Joachim Low decided to let him recuperate at Arsenal’s London Colney training ground instead of including him in the squad for their World Cup qualifying matches.
Contract negotiations between Arsenal and Ozil resumed at the start of the season and it is understood that chief transfer negotiator Dick Law, who helped bring the German from Madrid to north London in 2013, is still running several errands for the club despite leaving his post at the end of September.
Meanwhile, talks with Alexis Sanchez have come to a complete halt as the Chile international has made it clear he has no intention of signing a new deal.
Alexis came close to leaving the Gunners for Manchester City on transfer deadline day, with both clubs even having a verbal agreement, but the deal was dependent on Arsenal securing a world-class replacement in the form of Thomas Lemar.
That move for the Monaco winger fell through, however, after the player opted to stay at Monaco and that meant Alexis was denied his dream move of linking up with former manager Pep Guardiola.
The Chilean is able to sign a pre-contract with a foreign club in January and, while Paris Saint-Germain remain interested in the 28-year-old, City are still the favourites to secure his signature.