Manchester United are looking to pip their Premier League rivals to Abdoulaye Doucoure this summer.
Tottenham, Liverpool and Arsenal are also said to be interested in the midfielder, who has played an integral role in Watford's midfield this season.
The reports have suggested the United sent scouts to watch the in-form 25-year-old during Saturday's 1-0 win over West Brom.
Spurs manager Mauricio Pochettino also paid a personal visit to Vicarage Road last month as he watched Doucoure as he starred in Watford's 4-1 hammering of Chelsea.