Liverpool have emerged as frontrunners in the race for Doucoure, who has blossomed for Watford this season.
The 25-year-old has been a huge influence for the Hornets, making 23 appearances and scoring seven goals so far this season.
Liverpool are reportedly in the mix for his signature as Jurgen Klopp ponders replacements for Emre Can, who is primed to leave on a free transfer.
And the Mirror say Watford value the player at a huge £40million.
Hornets manager Javi Garcia praised Doucoure by saying: “If there is an offer, we will discuss to find the best solution.
“Everyone wants to play in the Champions League, the big competitions.”
The Mirror say Watford may be forced into selling Doucoure to Liverpool.
And that is because the club are keen to ensure they make another profit this season.
Watford made a £4million profit in the 2016-2017 season but selling their midfield bulldozer, and forward Richardson, may have to be done to balance the books.
Meanwhile, Doucoure recently talked up Liverpool and expressed a desire to play in the Champions League.
“Liverpool is a club that needs no introduction,” Doucoure said.
“I was impatient to play there at Anfield, I wanted to feel the atmosphere.
“For me it would be a dream to play in a club like this.”
He added: “It’s true that I’ve heard that clubs like that are interested in me in England, but there’s been nothing concrete. It’s true that I’d like to play in a team like that.
“Everyone wants to play in the Champions League, so that may mean going to a big club.”