Yeah as others have said I doubt the reason he got released was purely down to his injury. There's nothing wrong with playing semi pro football for a while, the glam is all about what academy you play for and who you know but sometimes you need to take a step back to take two steps forward. If he works hard and has the ability (also the opportunity), he will get his chances to impress higher up the pyramid. Look at Courtney Baker-Richardson, released by Cov at 18, few seasons at various semi pro clubs then Leamington now at Swansea.
The Academy system is very intense and sometimes it's better to be out of it than in it.
Good luck to the lad.