The 21-year-old had been a member of the Reds' setup since the age of nine and made one senior appearance for the club in an FA Cup fourth-round replay with Shrewsbury Town in the 2019-20 season.
Cain also made the bench for Jurgen Klopp in the Premier League, EFL Cup and Champions League, including in both legs of the Reds' quarter-final tie with Real Madrid in the 2020-21 campaign.
After spending the 2021-22 season on loan at Newport County, providing two assists in 28 games for the club, the midfielder has now left Anfield permanently to drop back down to League Two.
Prior to his exit, Cain came up with three goals and an assist in 13 games in the Premier League 2 this season - wearing the captain's armband in five of those matches.
The Englishman was an unused substitute in Liverpool's EFL Cup third-round win over Derby County back in September, and he played an integral role for the Under-18 side that won the FA Youth Cup in 2019.
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