Dennis scored ten times in the Premier League last season and was impressive despite Watford being relegated from the top tier.
Several Premier League teams have shown an interest in taking him away from Vicarage Road this summer, with the player keen to be in the top tier of English football again.
Nottingham Forest have been tracking the forward and are now considering whether to formalise their interest in the Nigerian.
But it has been claimed that they would prefer to sign the striker on an initial loan with an option to buy.
Watford are prepared to listen to offers for Dennis and have been waiting for concrete offers to land on their table.
The Hornets want clubs to match their £20m asking price.
Newcastle are also keen on Dennis and have also been considering whether to go in with a firm offer.
The Magpies and the Tricky Trees could battle for Dennis’ signature before the window slams shut.