Watford are targeting German coach Roger Schmidt as they step up their pursuit of a replacement for Walter Mazzarri.
Mazzarri's tenure ended after an alarming number end-of-season slump and Watford's campaign finished with a dreadful 5-0 home defeat by Manchester City.
Watford have interest in Marco Silva but the Portuguese coach, who will leave Hull, is more attracted to Southampton as well as clubs in Portugal and Spain.
Claudio Ranieri is not currently on Watford's wishlist, as the club's hierarchy are aiming to attract a more modern coach.