Born on 27 October 1993 in Croydon, 6ft 5in Jamal was ever-present in the FA Youth Cup-winning campaign of 2011/12, during which he put in some outstanding performances and made crucial penalty saves.
He joined the Academy fairly late, at Under-13, but has developed into an England Under-19 international.
As well as 19 youth team games in 2011/12, he made 11 reserve appearances and trained frequently with the first team keepers. He also took part in the first team's summer tour to the USA in the summer of 2012.
Blackman trains regularly with the first team goalkeepers but is yet to make his senior debut. He spent the majority of the 2012/13 campaign as the first-choice Under-21s' goalkeeper when not involved with the first team.
Blackman made his debut for England Under-19s in October 2011.