The 18-year-old striker was not included on Liverpool's pre-season tour of Asia and Australia due to "uncertainty over his future," notes O'Rourke.
Sinclair played 25 minutes across two substitute appearances in the Premier League last season, coming on against Chelsea and Crystal Palace as the campaign reached its conclusion, per WhoScored.com. He previously played just eight minutes while on loan at Wigan Athletic, who went on to be relegated from the Championship.
The Englishman scored four goals and provided three assists during 13 appearances in Liverpool's Under 21 side during 2014-15, per Transfermarkt.co.uk. He also scored six and assisted one in seven UEFA Youth League appearances.
B/R UK's Sam Tighe described Sinclair's qualities:
Sterling has been a key player for Reds boss Brendan Rodgers over the last three years, with versatile forward Jordon Ibe also breaking into the team during the recently concluded campaign.
Sinclair ranks among the next in line of those who could make an impression. He is a quick, agile and athletic frontman who is more than capable of gobbling up a range of chances, highlighted below:
Rodgers has signed strikers such as Mario Balotelli, Rickie Lambert and Danny Ings over the last two years, adding further hurdles to Sinclair's route into the senior team.
O'Rourke doesn't provide a reason why the player allegedly wants to move on, but considering Liverpool also have Daniel Sturridge and Fabio Borini among their ranks, Sinclair may wish to pursue first-team football elsewhere.
According to talkSPORT (h/t Charles Perrin of the Express), Rodgers could push for the signing of Aston Villa striker Christian Benteke, a deal which would also damage Sinclair's long-term prospects at Anfield.
Sinclair is a real talent, someone who could develop into a Premier League regular, so the Reds will need to tread carefully when potentially letting him move on.