The Nottingham Forest striker began his career at Watford.
Watford were previously low down the list of likely destinations for the striker, but have since risen to second favourites behind Middlesbrough [11/8].
Assombalonga began his career at Vicarage Road, but left for Peterborough United in 2013 and was sold to Nottingham Forest a year later for around £5.5 million.
Nottingham Forest’s Britt Assombalonga [left]
Though his City Ground career has been plagued by injuries so far, the 24-year-old has still managed to score 30 goals in 69 Reds appearances – prompting reports of interest from Middlesbrough, Burnley and Huddersfield Town in recent weeks.
And while Watford are yet to be formally linked with a move for the DR Congo-born star, they could be in the market for attacking reinforcements having seen January loan signing M’Baye Niang return to AC Milan.
The Hornets have already dipped their toes in the Football League pool this summer, landing Will Hughes from Forest’s local rivals Derby County.
It has been reported that Forest, who have already brought in Hibernian striker Jason Cummings this summer, are seeking double what they paid for Assombalonga.
Nottingham Forest’s Jason Cummings in action for Hibernian
Another bookmaker, Bet Victor, has Watford at 16/1 to sign Assombalonga.
Can Nottingham Forest keep hold of Assombalonga?
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