The 21-year-old forward’s future at Marseille has come under the scanner due to serious interest from a number of clubs in the Premier League.
And it has been claimed that one more Premier League side have joined the queue for the Marseille striker.
According to French sports daily L’Equipe, Watford have probed the possibility of signing the striker ahead of Monday’s transfer deadline.
Roy Hodgson has taken charge of the club and Watford are prepared to back him with funds in order to strengthen his squad in the fight for Premier League survival.
Dieng has been identified as a target and Watford are weighing up on making an offer for him.
Newcastle have told his representatives that they will try to sign him this month only after they land their primary targets.
Marseille are open to selling him but are yet to receive a concrete offer on their table for the forward.