The 30-year-old had been at the Emirates for a year-and-a-half after joining from Manchester United in January 2018 – a deal which saw Alexis Sanchez go the other way.
After an impressive start at Arsenal, Mkhitaryan came under scrutiny from fans and was eventually out of favour in north London.
The Armenian's wages were also a sticking point for Arsenal, who have managed to clear the decks in that regard this summer.
It is believed that Roma are picking up nearly all of Mkhitaryan's £200k-per-week wage.
However, it's understood that the Italian giants do not have an option to buy.
The player himself is unclear whether he'll return to north London in summer 2020.
"Let's first see what I can do at Roma, and at the end of the season I think we can talk about if I will have the possibility to stay or to go to something else, I don't know," he told VBET news (via The Sun).
"Now, I cannot say about the future, it's better to be focused on the next games."
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