Doucoure has scored seven times and registered three assists in 26 Premier League appearances for Watford this term.
The 25-year-old admitted earlier this week that he was interested in a move to Arsenal, but Gracia has insisted that the midfielder should just be focusing on helping Watford finish the 2017-18 campaign on a positive note.
"I do not know if there are big clubs interested in Doucoure or other players, but if there are clubs interested it is because they are playing well," Gracia told reporters. "I am only interested in them playing well and we will see what happens in the future."
Doucoure joined Watford from Rennes in the summer of 2016 following a loan spell at Granada.