4. Jack Robinson - 16 years, 8 months and 7 days
Jack Robinson's debut in 2010 under Rafa Benitez was once the record-holder for the club for the youngest-ever debut. He made a sub appearance against Hull City in the Premier League, coming off the bench in the 87th minute for Ryan Babel.
The English centre-back had two Championship loans while contracted by Liverpool, but he could never make it at the club. However, Robinson has gone on to have a respectful career, playing with multiple clubs in the Championship and three Premier League seasons with Sheffield United, where he currently plays.
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