According to journalist Matt Thielen, the approach so far amounts only to an exploratory contact rather than a formal bid, with City gathering information on Mac Allister's situation as they work through a shortlist of options to succeed Rodri in central midfield.
The 27-year-old endured a dip in form last season after an outstanding 2024/25 campaign in which he was one of the Premier League's standout performers, but rediscovered some of that quality for Argentina at this summer's World Cup, where he helped his country reach the final. He remains on holiday following that run but is due back at Liverpool's training base shortly.
No rumours had previously linked Mac Allister with an exit, but Liverpool are known to be looking for ways to raise funds this summer, still working to complete the signing of Bradley Barcola while also trying to move on several fringe players from an initial list of departures drawn up at the start of the window.
A club aware of Mac Allister's market value could yet be tempted by a substantial offer, even with the midfielder under contract at Anfield until 2028.
Mac Allister would not be City's only option to replace Rodri. The club is closing in on a deal for Lille's Ayyoub Bouaddi, 18, though that move is regarded as one for the future rather than an immediate fix.
Enzo Maresca's preferred candidate is a second Argentine, Chelsea's Enzo Fernández, 25, though a deal for the midfielder could cost as much as €150m, a figure that may ultimately push Manchester City towards a cheaper alternative.