Billy McKinlay has left Watford after just two games in charge, according to Sky sources.
McKinlay lasted just eight days at Vicarage Road after succeeding Oscar Garcia, making his reign the sixth shortest in English football history.
Garcia's own spell in charge lasted only three weeks before health reasons led to his departure, and Watford are now looking for their fourth manager in six weeks.
McKinlay quit his job as Northern Ireland No 2 last month to take over in Hertfordshire, securing four points from a possible six in his two games.
Watford are currently third in the Championship and their next game is a trip to Sheffield Wednesday after the international break on October 18.