Lee scored in West Ham's development squad defeat to West Bromich Albion on Monday.
West Ham fans love nothing more than seeing a homegrown Hammer progress from the Academy into the first team.
Marked his competitive debut with a goal
There have long been calls from the terraces for Lee to be given his chance in the senior side.
And when that chance came, for a Europa League qualifier against FC Lusitanos in Andorra last month, the 20-year-old didn't disappoint, marking his first start with a goal in a 1-0 win.
Bilic was not officially in charge for that match and since he took over Lee has been used sparingly with the likes of outcast Modibo Maiga preferred instead.
The highly rated son of former England star Rob showed his determination to make a real go of his Hammers career by returning to pre-season training early in a bid to feature for the club's first team.
A regular scorer at both youth and reserve level, Lee found game time difficult to come by during Allardyce's four-year tenure, for which Big Sam was castigated by some supporters.
Loan spells at Colchester United and Luton Town saw the burly and pacy striker net his first senior goals either side of an ill-fated stint at Southend United where he sustained a hamstring injury in his first training session.
Bilic's preference for outcast Maiga tells its own story
But crucially his latest demotion to the reserves comes despite West Ham desperately struggling in the striking department.
Andy Carroll is still out with his long-term injury and Enner Valencia has been ruled out for three months.
It leaves Diafra Sakho as West Ham's only proven Premier League goalscorer.
But the likes of Maiga, who has no future at the club, have been preferred over Lee so far this season in what looks a damning indictment of Bilic's opinion of the young Englishman.
Age cannot be a factor because the former Croatia boss has already shown in the case of 16-year-old Reece Oxford, if he feels a player is good enough he will play them.
Lee admitted earlier this summer he is desperate to finally kick-start his Premier League career.
But his future at the club looks in doubt and now he may well be loaned out or sold, particularly if West Ham make good on speculation that they will bolster their squad with a major striker signing this month.