A leggy midfielder who has impressed in a central role and finished the 2015/16 season in style, Willock was formerly with Arsenal.
The youngster still has two brothers on the Gunners' books but he had trials with Reading and Sunderland before earning a switch to Manchester.
An acquisition in the summer of 2012, he was not deemed ready for Under-18 action in his first year but impressed at the Milk Cup in Northern Ireland.
He appeared to shoot up in height, covering the ground in effortless fashion, and holding down a role in central midfield for Paul McGuinness' side, making a superb start to the campaign. A key contributor with his energy and distribution, he got off the mark at Under-18 league level with a superb long-range strike during the win against West Brom in October.
By making more appearances than any of his colleagues, 29 in total, he proved a valuable asset to the team and often performed an unsung role in the engine room. Nonetheless, his progress did not go unnoticed as he was elevated to Warren Joyce's Under-21 squad and came off the bench in the goalless draw with eventual champions Chelsea.