The 19-year-old is set to be a free agent in a few months’ time and has been linked with a move away from Anfield in search of game time for a while now.
The teenager has been highly thought of on Merseyside for some time, but despite being the club’s youngest ever player after making his debut back in 2012 at the age of 16, he’s been unable to push into the senior set-up.
Jurgen Klopp fielded him against Exeter in the FA Cup third round over the winter, yet despite his goal in Devon the striker has been unable to build upon this.
Sinclair is likely to play a back-up role to Odion Ighalo and Troy Deeney at Vicarage Road.
Liverpool will be entitled to a compensation fee due to the attacker’s age.
Sinclair is not the only member of Klopp’s ranks being linked with Watford, as both Joe Allen and Jordon Ibe are thought to be on the Hornets’ agenda.