Watford have placed Under-23s coach Hayden Mullins in charge for Wednesday's Premier League trip to Leicester City following the sacking of Quique Sanchez Flores.
Flores' second spell at Vicarage Road was brought to an end at the weekend on the back of a 2-1 loss to Southampton that left the club bottom of the division.
Watford hope to bring in a permanent successor "imminently", but Mullins will be in the dugout for the midweek clash with the high-flying Foxes.
The 40-year-old has been a coach at Watford since July 2016 and was brought in to oversee first-team training on Monday, alongside head of academy goalkeeping Graham Stack.
Former Newcastle United and Brighton and Hove Albion boss Chris Hughton is rumoured to be one of the frontrunners for the Hornets post.