The midfielder is out of contract at the end of the season and was expected to extend his stay at the club he joined five years ago.
Inter Milan had been heavily interested but reports this week suggested Herrera was keen to stay in England.
But the saga has taken a shock U-turn, with The Sun reporting that the 29-year-old now looks likely to leave following discussions with PSG.
The report claims Herrera will earn a hefty £150,000-a-week with the French giants.
Despite struggling for form earlier on in the season, the Spaniard has been a mainstay in the side since Ole Gunnar Solskjaer took charge.
And with the Norwegian expected to land the gig permanently, a new contract for Herrera seemed inevitable.
But with no transfer fee required, PSG have been able to outbid United on wages.
The shock revelation comes amid news that:
“He’s a hostage to PSG.”
PSG star Adrien Rabiot’s agent
Solskjaer will now be in the market for a new central midfielder and Adrien Rabiot is an option after falling out of favour at PSG.
The Frenchman is a free agent at the end of the season and is yet to agree terms with another club.
Veronique Rabiot, his mother and agent, told L’Equipe: “Adrien is a prisoner.
“He’s a hostage to PSG.
“This environment is cruel. A footballer is made to play, not to stay in the closet.
“Adrien has not played since December, and probably until June.
“He is taken hostage because he does not want to re-sign while he is only respecting his contract.
“Adrien asks only that: to respect his contract.”