Watford have reportedly already made an unsuccessful approach for former Athletic Bilbao boss Jose Angel Ziganda.
The Hornets are looking for their ninth permanent manager since 2013 and their third this season after they let Quique Sanchez Flores go following Saturday's 2-1 defeat to Southampton.
The result left the club six points from safety at the bottom of the table and they were thought to be pursuing a quickfire appointment as they look to avoid a relegation battle in the second half of the season.
Sky Sports News reports that while Watford are now prepared to take a more measured approach to finding Flores's successor, they did speak to Ziganda, who left his role with Bilbao in May 2018, on Tuesday, albeit to no avail.
Chris Hughton, Roger Schmidt and Paul Clement have also all been linked with the role, while former England boss Sam Allardyce has expressed his interest in taking up the position.
Hayden Mullins oversaw training on Monday and he is expected to be in charge for their game with Leicester City on Wednesday.
