The Red Devils reached a trade agreement with their Premier League rivals in January as Sanchez arrived at Old Trafford and Henrikh Mkhitaryan moved in the opposite direction.
That switch has not proved as positive as Jose Mourinho was hoping, with a Chilean forward struggling to make his mark in Manchester.
Another move has been rumoured, while Ozil is no longer considered to be key component of the Arsenal side as Unai Emery delivers positive results during an injury-enforced absence for the German.
Parlour believes the World Cup winner still has a role to play for the Gunners and cannot see an obvious fit in the transfer market, telling talkSPORT: “I still think he is a very important player for the squad.
“I don’t know how you value him, because you have got to look at his wages, he is on a reported £350,000 a week.
“Who is going to pay that money? I think you are going to find it really tough for someone to pay that sort of money in wages.”
Asked what Ozil could be worth, Parlour added: “To value Ozil in this market, I would say £40m to £50m.”
The former Arsenal star has, however, suggested that a swap deal could be considered by United.
That would allow them to move out one faltering star and bring in another creative influence, but whether any of those involved in the mooted agreement would be interested remains to be seen.
Parlour added on Ozil’s links to United: “Where would he fit in there though? Would he be a player that they need?
“They have tried one [Alexis] Sanchez haven’t they? Would they lose Sanchez and get in Ozil? Would there be a swap deal?
“I think it will come down to the wages. I would be surprised if they did.”
Arsenal tied Arsenal to a lucrative new contract in January, while Sanchez earned a considerable increase to his salary when penning a four-and-a-half-year deal at Old Trafford.