The 25-year-old winger has emerged as a priority target for the Saudi club, having previously turned down an approach from Galatasaray worth €45 million.
This time, Martinelli appears willing to consider the move, with Arsenal reportedly seeking around €70 million to sanction his departure.
Manager Mikel Arteta left Martinelli out of the squad for both the Community Shield and Arsenal's opening Premier League fixture, a clear signal that the Brazilian is no longer guaranteed a starting role at the Emirates.
Arsenal are not expected to stand in his way if a satisfactory offer arrives, having already strengthened their options on the flanks this summer with the signing of Greek winger Christos Tzolis following Leandro Trossard's departure.
For Arsenal, a sale would represent a substantial windfall on the roughly £6 million they paid to sign Martinelli from Brazilian club Ituano back in 2019, and the north London club are said to be seriously weighing the financial opportunity as they continue their own summer spending.
Martinelli, who is under contract until 2027, has made over 200 appearances for Arsenal since his move from Brazil, but has found first-team opportunities harder to come by following the club's continued investment in attacking areas.
Galatasaray's interest has not entirely disappeared, though Martinelli's camp made clear at the time that a move to Turkey held little appeal, leaving Al-Hilal as the more advanced and, for now, more likely destination should a fee be agreed with Arsenal in the days ahead.
Martinelli broke into Arsenal's first team quickly after his arrival from Brazil, becoming a key part of the side that pushed Manchester City close in successive Premier League title races, and signed a long-term contract extension in 2022 that reflected his standing as one of the squad's most important young players at the time.
His influence has waned somewhat over the past two seasons, however, as Arsenal have added significant attacking depth and increasingly rotated their forward line, leaving Martinelli competing for minutes rather than guaranteed a starting berth.
A move to the Saudi Pro League would mark a considerable departure from the trajectory many had expected for the Brazilian only a few years ago, when he was regularly linked with a step up to a genuine European superclub such as Real Madrid.