Fabrizio Romano confirmed the move, reporting Manchester City's offer as their first formal approach for the 34-year-old Argentine. City are targeting Rulli as a direct replacement for James Trafford, who is closing in on a £40m switch to Leeds United after growing frustrated with limited game time behind Gianluigi Donnarumma last season.
Rulli would arrive as understudy to Donnarumma rather than a guaranteed starter, but sources close to the move say the goalkeeper is "very keen" on a move to the Etihad Stadium and has already agreed personal terms on a two-year contract. City's opening offer stands at around €2m, while Marseille are said to be holding out for closer to €3.5m, leaving a gap still to be bridged before any deal is finalised.
It would mark an unlikely homecoming for Rulli, who joined City on loan in August 2016 but never made a first-team appearance before moving on, leaving without featuring in an official match during his half-season on the books.
Since then he has built a solid career across Spain, France and the Netherlands, with spells at Real Sociedad, Villarreal and Ajax, before establishing himself as Marseille's first-choice goalkeeper under Roberto De Zerbi. He made 39 appearances in all competitions for the Ligue 1 club last season, keeping nine clean sheets, and has earned eight caps for Argentina, featuring at both the 2022 and 2026 World Cups, the latter as part of the squad that reached the final.
Marseille are believed to be relaxed about a sale, having already lined up Toulouse's Guillaume Restes as a long-term successor, though the French club are also negotiating goalkeeper Jeffrey de Lange's proposed move to FC Twente and are keen to avoid losing both senior stoppers before a replacement is secured.
Sporting CP have also shown interest in Rulli, but City are understood to be the frontrunners for his signature, with Trafford's Leeds move expected to be the trigger that finally unlocks the deal on City's side.
Should the transfer go through, Rulli would slot in as competition and cup cover for Gianluigi Donnarumma rather than as a guaranteed starter, continuing City's pattern under new head coach Enzo Maresca of adding experienced, low-risk depth to the squad.