The Gunners fended off interest from Wolverhampton Wanderers to complete the signing of Marquinhos from Sao Paulo in the summer of 2022.
The Brazilian got off to an impressive start, scoring a goal and providing an assist on his debut against FC Zurich in a Europa League group-stage encounter.
However, the attacker has been unable to build upon that encouraging display, having gone on to make a total of six appearances for Mikel Arteta's side.
After returning from an unsuccessful loan spell with Nantes last month, Marquinhos is set to head back out the exit door in the coming days.
According to The Standard, Marquinhos has given the green light to return to Brazil and join Fluminense in a loan deal.
The report claims that Fluminense will pay a loan fee, and they will have the option to make the move permanent if certain clauses are met.
Marquinhos was also said to be a target for Corinthians, but he has opted to join Fluminense after being impressed by their head coach, Fernando Diniz.
The 49-year-old oversaw significant success last season, guiding the club to their first-ever Copa Libertadores trophy.
Arsenal are ultimately prepared to allow Marquinhos to leave, with the youngster unable to force his way into Arteta's plans.
The likes of Bukayo Saka, Gabriel Martinelli, Leandro Trossard and Reiss Nelson are all above Marquinhos in the pecking order.
The youngster was unable to make a significant impression in either of his two loan spells, registering just one goal and one assist in 11 games for Norwich City in the second half of last season, while he only made seven appearances for Nantes in the first half of the current campaign.
Marquinhos is set to complete the move to Fluminense after spending the last three weeks representing Brazil Under-23s in the Pre-Olympic tournament.