Liverpool confirmed their teamsheet for the latest Premier League fixture at 1pm on Sunday, with the average age of Jurgen Klopps substitutes just 20 years old.
The youngest of those is Nyoni, who makes the first-team squad for the first time.
It comes just three months after the teenager completed a summer move from Leicester, as part of Liverpools ongoing focus on recruiting elite-level youngsters from the UK.
A versatile midfielder, Nyoni has largely spent his time as part of the U18s so far, though in recent weeks he has become a fixture at U21s level.
That has included back-to-back starts in the last two U21s games, with an assist for Mateusz Musialowskis wonderstrike in the 2-1 defeat to League Two side Barrow on Tuesday night.
In 10 games for the clubs academy sides so far this season, Nyoni has scored four goals and laid on five assists.
Nyoni has also trained regularly with the senior side, and has clearly caught the eye of Klopp and his staff in the process.
He is very highly rated within the club, which vindicates his decision to turn down almost every other top club in England in favour of a move to Merseyside.
If he comes on, Nyoni would become Liverpools youngest-ever league debutant at 16 years, four months and 13 days, breaking the record currently held by Jack Robinson.
The clubs youngest-ever player across all competitions remains Jerome Sinclair, who debuted in the League Cup just six days after his 16th birthday in 2012.
While Nyonis inclusion in the matchday squad against Brentford is enforced by injuries to the likes of Curtis Jones and Ryan Gravenberch, there is a firm belief in his ability and potential.
He is capable of playing in a variety of roles in midfield, and has showcased his fine range of passing, smart interplay and work rate off the ball since joining.
Such is the surprise over his involvement vs. Brentford, however, that the teenager was not even included on the back of Liverpools official matchday programme.