Arsenal is looking to sign Mari on loan until the end of the season with an option to buy.
The Spaniard signed a contract with Manchester City in 2016, but never made an appearance.
He went out on loan for three successive seasons to Girona, NAC and Deportivo La Coruna, before joining Flamengo on a permanent deal last summer.
The 26-year-old would become Mikel Arteta’s first signing since taking over as Arsenal’s head coach in December.
Mari featured in 22 of Flamengo’s 38 games as they won the Brazil’s Serie A, scoring twice as Flamengo finished 16 points clear of Santos and Palmeiras.
Meanwhile, Arsenal will have to pay £30m if they are to sign Ukrainian defender Mykola Matviyenko from Shakhtar Donetsk.