Marco Silva has emerged as Watford's leading managerial target but they face competition for his services, sources close to the club have told ESPN FC.
The future of Hull City boss Silva is uncertain following their relegation from the Premier League, and the sources said he is highly regarded at Watford.
The Hornets confirmed this week that Walter Mazzarri will be leaving after the final Premier League game of the season at home to Manchester City on Sunday.
Silva impressed at Hull, giving them a chance of survival after succeeding Mike Phelan at the KCOM Stadium in January.
But a crucial home defeat to relegated Sunderland, followed by a heavy loss at Crystal Palace, sent them down.
Silva is out of contract at the end of the season and has attracted the attention of several clubs across Europe, with Premier League, La Liga and Portuguese sides monitoring his situation.
But he could have reservations about the Watford post as the club have changed managers at the end of each of the last three seasons.