Morgan's deal had been due to expire at the end of this season but The U's have severed their ties with the youngster.
The 19-year-old made his first-team debut almost three years ago and was a regular in the Second Division outfit's side last term.
Though he was primarily deployed as a substitute by The U's, Morgan had still managed to amass 78 appearances for the club.
But he had not played for the Layer Road club this term after struggling with injury and he must now look elsewhere to put his career back on track.
