Mayor Giuseppe Sala has revealed Milan council is open to the possibility of selling San Siro to Inter and AC Milan.
The Italian giants announced in July they had taken the first steps to replacing their iconic home with a new 60,000-seater stadium after filing a proposal with local authorities.
Inter and bitter rivals Milan have a long-running lease on San Siro, though it is in need of significant regeneration.
However, Sala said he wants to see the two teams remain at their current ground – which is owned by the city of Milan - and has offered them an alternative option.
"Right now, there are two possibilities on the table - a [new] stadium in San Siro or a stadium in Sesto San Giovanni," Sala told Corriere della Sera.
"I'd add a third - we're willing to sell San Siro, should the possibility be considered.
"The construction of the new stadium is a possibility that we dread, and it obviously wouldn’t be welcome for us, but we're talking about two privately-owned clubs that, in their rightful interests, could do something like that."
Sala stated the current venue is valued at somewhere in the region of €70million, adding: "The council doesn't want to make any money from San Siro. We're extremely willing to let a third party perform an assessment, telling us how much it's worth.
"We have absolutely no need or interest to speculate about San Siro. I estimate San Siro to be worth around €70m.
"We could use an independent body as a surveyor, so that there's no speculation.
"That said, the clubs are within their rights to choose. If they prefer, for reasons of their own, to build a new stadium, that's what they'll weigh up.
"I can only try to persuade them with all the possibilities on the table and, right now, I’m also offering this possibility."